Users Online: 673 Home Print this page Email this page Small font sizeDefault font sizeIncrease font size
 

 

Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
     

 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 64  |  Issue : 2  |  Page : 178-185  

The use of emergency contraceptive pills in India: A meta-analysis


1 Independent Researcher, Prayas Health Group, Pune, Maharashtra, India
2 Senior Researcher, Prayas Health Group, Pune, Maharashtra, India

Date of Submission01-Oct-2019
Date of Decision07-Nov-2019
Date of Acceptance27-Apr-2020
Date of Web Publication16-Jun-2020

Correspondence Address:
Shrinivas S Darak
Prayas Amrita Clinic, Athawale Corner Building, Sambhaji Bridge Corner, Karve Road, Deccan Gymkhana, Pune - 411 004, Maharashtra
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijph.IJPH_494_19

Rights and Permissions
   Abstract 


Background: Unplanned pregnancies are a major public health concern. In India, 33% of an estimated 48.1 million pregnancies end in induced abortions. Emergency contraceptive pills (ECPs) can prevent pregnancy after sexual intercourse, have been part of India's family planning program since 2002–2003 and are available as over-the-counter drugs. While there are concerns about the overuse of ECPs, the pattern of use of ECPs in India is unknown. Objectives: The objective is to determine the proportion of women who have ever used ECPs and repeatedly used ECPs and also to assess the reasons for use and nonuse of EC pills along with factors associated with the use. Methods: A systematic review of ECP use in India was conducted by electronically searching three databases-PubMed, Popline, and Google Scholar. All studies were published between 2001 and 2017, and the electronic search was last conducted in July 2018. The proportion of use was calculated using meta-analysis, and the other factors were assessed by narratively synthesizing the findings. Thirty-three articles met the inclusion criteria. Results: The pooled proportion of women who ever used ECPs was 6% (95% confidence interval, 0.03–0.10). The proportion of repeat use ranged from 12% to 69%. Five studies reported reasons for not using ECPs, and the most common reasons were religious/cultural beliefs followed by fear of side effects and inadequate knowledge. Studies to understand sociodemographic and other factors affecting the use of ECPs in India are lacking. There are significant concerns about the quality of the studies. The definition of repeat use of ECPs is inconsistent across papers. Furthermore, judgmental attitudes of health-care providers were apparent in some papers. Conclusion: The review highlights important research and program gaps.

Keywords: Emergency contraceptive pill, India, systematic review, women


How to cite this article:
Mehta NR, Darak SS, Parchure RS. The use of emergency contraceptive pills in India: A meta-analysis. Indian J Public Health 2020;64:178-85

How to cite this URL:
Mehta NR, Darak SS, Parchure RS. The use of emergency contraceptive pills in India: A meta-analysis. Indian J Public Health [serial online] 2020 [cited 2020 Sep 23];64:178-85. Available from: http://www.ijph.in/text.asp?2020/64/2/178/286820




   Introduction Top


Unplanned pregnancies are a major public health concern. Globally, 210 million pregnancies occur each year, of which 80 million are unplanned.[1] In developing countries, 214 million women who want to avoid pregnancy are not using a modern contraceptive method.[2] In India alone, 33% of estimated 48.1 million pregnancies end in induced abortions.[3]

Emergency contraception (EC) is a method of contraception that can be used to prevent pregnancy after sexual intercourse. Emergency contraceptive pills (ECPs) are recommended for use within 5 days of intercourse but are more effective if used sooner.[4] They were officially introduced under the Family Welfare Programme in 2002–2003,[5] are now part of the Essential Drug List for primary healthcare in India[6] and have been included in ASHA worker's and ANM's kits.[7] In 2005, they became available as over-the-counter drugs.[8],[9],[10] As a result, there have been concerns among health-care providers in India over the overuse/misuse of ECPs.[8] While anecdotal evidence shows a rise in ECP sales, scientific evidence shows low proportions of use.[11],[12],[13] Despite easy availability, the level of awareness of ECPs remains limited.[14],[15],[16] In 2015–2016, around 85% of women were aware of oral contraceptive pills (OCPs) and only 38% had knowledge of ECPs.[11] According to the National Family Health Survey (NFHS-4), only 0.4% of women had ever used ECPs.[11]

To resolve this discrepancy, we conducted a systematic review (SR) and meta-analysis of the available literature on ECP use in India. We aimed to understand what proportion of women use EC pills and what are the factors associated with its use. The main objectives of the study were to determine the proportion of women who: (a) have ever used ECPs and; b) repeatedly use ECPs. We also assessed the reasons for use and nonuse of EC pills along with factors associated with its use.


   Materials and Methods Top


Criteria for considering studies for this review

Type of participants: We included both married and currently single (unmarried, divorced, and widow) women between 15 and 45 years of age with no reported disability that might make them more prone to side effects. If the study had both male and female participants, we included only female participants for the meta-analysis. Animal experiments were excluded.

The ECPs included in this review were all doses of oral Levonorgestrel (LNG) only. Articles focussing on use/repeat use of ECPs or side effects associated with use were included. Studies in which LNG was used as a regular or intrauterine form of contraception were excluded.

Outcome measures: The primary outcome measures employed were quantified measures of use/repeat use of ECPs. Secondary outcome measures sought were-reasons for using/not usingECPs and factors associated with ECP use.

Type of studies: Primary studies assessing the use/repeat use and the factors associated with ECP use were included. Articles confined to India and published in the English language were included.

Search methods for identification of studies

The electronic search was last conducted in July 2018 on three databases-PubMed, Popline, and Google Scholar. Detailed search strategies with relevant search terms were developed for each database [Appendix 1]. Zotero 5.0 was used as the management software. All references cited in the included articles were hand searched for additional studies.



Selection of studies

One investigator (NM) reviewed the titles and abstracts of articles identified in the search using the inclusion/exclusion criteria. At this stage, an article was included, even if there was an uncertainty regarding its inclusion. After title and abstract screening, two investigators (RP, SD) reviewed the articles, and disagreements were resolved by discussion before moving on to full-text screening. A group library was created on Zotero 5.0, and full reports of all included studies were obtained for assessment.

Data extraction and management

A data extraction form was designed, and data extraction was performed on two pilot articles for training and calibration. All investigators reported back, and there was a discussion on the design of the form, the outcome measures, and the exclusion/inclusion criteria. On discussion, the data extraction form was altered and designed in a Google sheet to extract information on the-bibliographic details, study characteristics, methodological characteristics, outcomes of interest, and funding source.

Data synthesis

Use/repeat use of ECPs has been reported as a proportion or as the number of participants using ECPs. The proportion of use was calculated along with the appropriate 95% confidence interval (CI), and meta-analysis was performed in R software. Subgroup analyses were undertaken for studies conducted in facilities versus communities to examine the difference in ECP use. Heterogeneity was assessed with the I2 statistic. A random-effects model was employed to account for variations between studies as well as variations within studies. Given the heterogeneity in the studies, the random effect model was considered a better-suited model.


   Results Top


Description of studies

The electronic search yielded 284, and hand searching yielded 11 relevant articles. Thirty-one duplicates were removed, and 222 after the title and abstract screening and nine after full-text screening were found ineligible [Figure 1]. All articles included in the study (n = 33) were published between 2001 and 2017. In all, 30 provided quantitative information on ECP use/repeat use, and one was a case study on adverse effects of LNG, and one each assessed attitudes of gynecologists and practices of pharmacists. Twenty-seven cross-sectional studies were included in our meta-analysis, and the remaining articles (n = 6) were analyzed separately. The studies were conducted across India [North (n = 13), South (n = 10), East (n = 4), Central (n = 3)]. Fourteen studies failed to report the study area [Table 1] and [Table 2].
Figure 1: Flow chart showing selection of studies

Click here to view
Table 1: Details of cross.sectional studies reporting use/repeat use of emergency contraceptive pills

Click here to view
Table 2: Details of other studies exploring various dimensions of emergency contraceptive pills use

Click here to view


Study characteristics

The pooled sample size of the studies included in our meta-analyses was 12003 participants. Of these, three studies did not report the study site, and only seven gave a detailed description of the sampling methods. All studies conducted in facilities used purposive sampling methods.

Characteristics of the study population

Nine studies were conducted on married women, nine on married and currently single and one on unmarried women. Eleven studies did not report the participant's marital status. One study was conducted among female sex workers (FSWs). Two studies (Arora 2005 and Mandal 2012) had both male and female populations; however, the male participants were excluded during meta-analysis. While 27 studies reported participant's literacy level, only ten studies reported their socioeconomic status. Fourteen articles reported the use of regular methods of contraception and 11 reported the side effects associated with ECP use.

Primary outcome measures

Use of emergency contraceptive pills

Of the 27 cross-sectional studies, 22 reported use and five reported both use and repeat use of ECPs. The proportion of ECP use ranged from 0% to 73%. The pooled proportion of women who ever used ECPs was 6% (95% CI, 0.03–0.10) [Figure 2]. Five studies reported that none of the participants used ECPs. The data reported in two articles (Arora 2005 and Mishra 2017) was misleading/confusing.
Figure 2: Forest plot of pooled proportion of emergency contraceptive pills use.

Click here to view


For the subgroup analysis, studies conducted in communities and colleges (n = 11) were pooled together. The sample size of the studies conducted in community settings ranged from 103 to 1448, with a combined total of 3935 participants. The pooled proportion of women who ever used ECPs in communities was 5% (95% CI, 0.03–0.08). The sample size of the studies conducted in facilities ranged from 131 to 1474, with a combined total of 6792 participants. The pooled proportion of women who ever used ECPs in facilities was 7% (95% CI, 0.02–0.15). This difference between the two settings could be as a result of including women seeking an abortion as participants in facility-based studies or using purposive sampling techniques.

Two prospective cohort studies assessed the use of ECPs among women who were offered counseling and advance provision of ECPs. It was observed that having advance supplies of ECPs did not increase their chances of having unprotected sex. However, if they did have unprotected sex, those with advanced supplies were more likely to use them. Despite improved accessibility, ECPs did not substitute regular methods of contraception.

Repeat use of emergency contraceptive pills

In all, eight studies reported data on repeat use. Of the five cross-sectional studies that reported repeat use of ECPs, the proportions ranged from 12% to 69%. The study assessing practices of pharmacists (Mishra 2013) found that pharmacies sold a mean of 62 packs a month. Of 60 pharmacists, 62% claimed that the majority of their customers repeated use in the same month. Only two pharmacists claimed that the same clients bought ECPs 30 times a month.

Among the two prospective cohort studies, Rocca et al. reported that 46% of women used ECPs two/more times, whereas Ellertson et al. reported no-repeat use. Women were offered an advanced provision of ECPs in both and although the proportion of repeat users appears high, it is important to note that this reuse is spread over 1 year. Frequent ECP use in the same menstrual cycle was low. Although limited, the evidence clearly nullifies health-care providers concerns of irrational use/overuse.

None of the authors provide information on repeat use in the same menstrual cycle. All, except one, have conducted studies in facilities, thus questioning the representativeness of the findings.

Secondary outcome measures

Reasons for using/not using emergency contraceptive pills

Six studies explored this aspect, and the most common reasons for using ECPs were unprotected intercourse and condom slipped/tore. Other reasons for using ECPs were (i) missed OCPs, (ii) miscalculated timing, (iii) unplanned sex, and (iv) unavailability of regular contraception.

Five studies reported reasons for not using ECPs, and the most common reasons were religious/cultural beliefs followed by fear of side effects and inadequate knowledge (on dosage/timing of use, access points).

Factors associated with emergency contraceptive pill use

Ten studies provided data on ECP use by sociodemographic factors. However, the data were not sufficient for subgroup analysis. Six articles reported use by area, two by socioeconomic status, and one each by literacy level and marital status. Women's contraceptive practices change with sociodemographic characteristics; however, studies do not take much cognizance of it. This review captured data on social/cultural factors associated with ECP use.

In their study, Khan et al. found that gynecologists play an unfavorable self-identified role of moral policing, where negative judgments are made about ECP users. Three-quarters of them considered marriage an important criterion for appropriate ECP use.

A gynecologist said that:

“I do feel that easy availability of ECPs has increased sexual contacts among young girls. There is a lot of misuse of ECPs by the current generation. With the influence of western culture and values, young people view casual sex as a normal activity, making the pill a powerful tool in a woman's hands.”

This review also explored the decision-making paradigm of family planning and ECP use. While ECPs are easily available, a myriad of factors come to play depriving women of the right to control their own bodies/pregnancies. In India, gender norms, power relations, and sociocultural values/beliefs limit opportunities for women.[17],[18] A woman's “value” within/outside her family is merely reduced to her ability to reproduce. Rocca et al. reported that most women opted out of their study citing the husband's disapproval, and 67.6% asked their husbands for permission before participating. Two studies found that in-laws were consulted 1.71% and 10.8% of the times, indicating the power relations that are deeply ingrained in our society where the power to make decisions still lies in the hands of men/in-laws.

Quality assessment

The meta-analysis of observational studies in epidemiology guidelines was used to report this review.[19] Quality assessment of the included studies was done by one investigator (NM) and rechecked during data analysis. The Newcastle Ottawa Scale (NOS) adapted for cross-sectional studies was used to assess the quality of 25 cross-sectional studies,[20] and the NOS for cohort studies was used for two prospective cohorts and one prospective observational study.[21] Two studies (Arora, 2005 and Mishra, 2017) provided confusing/misleading data and were not considered for quality assessment. Each article was scored individually according to the scoring criteria. Of the cross-sectional studies, 19 scored ≤4, five scored five and one scored six points [Appendix 2]. While the overall quality of cross-sectional studies was poor, the quality of cohort studies was good.



This review came across studies that failed to report the place of study, study area, and study site. Most did not enquire about participants' sexual behaviors/marital status. Some failed to give details of the methods used for randomization.


   Discussion Top


This SR found that overall, 6% of women used ECPs. The proportion of ECP use was 5% and 7% in community and facility-based settings, respectively. The proportion of repeat use ranged from 12% to 69%. Studies to understand sociodemographic and other factors affecting the use of ECPs in India are lacking. Furthermore, the judgmental attitudes of health-care providers were apparent in some papers.

This is the first study to document pooled proportions of ECP use in India. The proportions significantly differ from the proportion of ECP use reported by the NFHS-4 survey (0.4% women ever used ECPs).[11] Our data must be interpreted with caution as the studies included are smaller low-quality studies, and the NFHS-4 is a much larger survey of representative households. The pooled proportion of ECP use varies according to the study site (community vs. facility). This difference could be because facility-based studies included women seeking abortion. The likelihood of these women using ECPs is clearly different from women seeking regular contraceptive services; however, none of the studies explored these differences.

The proportion of repeat users ranged from 12% to 69%. We came across a study that assessed repeat use in Kenya and Nigeria that considered using ECPs 1–4 times/month as the threshold for repeat use.[22] However, repeat use is inadequately explored and there is no clarity on its definition. There was substantial confusion even among gynecologists regarding its definition.

The most common reason for not using ECPs was religious/cultural beliefs. Citing religious beliefs is associated with the fact that ECPs are believed to be abortifacients, and in most cultures, abortion is a taboo. Another study conducted in India reported that the use of ECPs may be deterred by religious/cultural beliefs.[23] A similar Pakistan based study reported that four-fifths of the participants believed that using ECPs was an “evil” practice.[24]

The included studies failed to assess factors associated with ECP use (socioeconomic status, literacy levels, age, marital status, occupation). Understanding these characteristics can help programs develop need-based interventions. There is also a limited representation of unmarried/single women and FSWs.

Some studies included in this review highlighted the judgmental attitudes of healthcare providers. Gynecologists believed that ECP users have risky sexual behaviors, multiple sex partners, premarital sex, sexually transmitted infections, and substitute regular contraceptive methods for ECPs. Another study in India reported that influential gynecologists passing moral judgments or having reservations about ECPs was a barrier to easy access to ECPs.[8] A similar Canada-based study reported that participants often received stigmatizing messages from providers when they sought ECPs.[25] The available literature, however, completely nullifies their concerns.[26] This review came across two studies in which giving advance supplies of ECPs to participants did not increase their likelihood of unprotected sex. They also reported that women did not substitute regular contraceptive methods for ECPs. There have been speculations that the number of young/unmarried girls seeking abortion has reduced as a result of ECPs. However, there is little/no evidence to support this change.


   Conclusion Top


This review has found that 13% of women ever used ECPs in India. Nausea, vomiting and menstrual problems were the most common adverse effects associated with ECP use. Understanding patterns of ECP use or factors associated with ECPs was not feasible owing to the lack of evidence. Women seeking ECPs can be assured that ECPs are not abortifacients and can be used to avoid pregnancies.

Studies should collect data on ECP use “in the last 12 months” instead of “ever use.” A time frame provides a better understanding and addresses problems like recall bias. It is a futile attempt on the author's part to assess ECP use without collecting data on participant's sexual behaviors. Authors must follow reporting guidelines and give details of study characteristics, study population, and recruitment methods to improve quality/transparency of studies. There is a dire need: (i) for consensus on a definition of repeat use well correlated with adverse effects, (ii) to explore sociodemographic factors associated with ECP use/repeat use and (iii) to understand the public health impacts of ECP use on unwanted pregnancies (cost-benefit analyses).

ECPs are an important female-controlled contraceptive method, and women should be empowered/enabled to make their own decisions and control their own pregnancies. At the same time, counseling husbands/partners is required. While simple measures like advance provision of ECPs will enable us to address the problem in the short term, a multi-sectoral approach where family programs include/collaborate with life-skills training programs can bring about the necessary changes. Pharmacies and private doctors are the most common sources of ECPs. It is important to facilitate access to ECPs through the public health sector. Negative attitudes of the society and health-care providers regarding ECPs need to be addressed. They should be sensitized to get rid of the stigma surrounding ECPs. In the current discourse, ECP use is mostly understood in the context of marriage. It is necessary to ensure easy access irrespective of marital status.

Acknowledgment

We would like to thank Valérie This Bernd from the University of Bordeaux for initiating this work as part of her master thesis. We are grateful to our colleague Dr Vinay Kulkarni for reviewing the draft and providing valuable feedback. We are thankful to Trupti Darak and Shamoita Bose for their useful inputs.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Abawi K, Chandra-Mouli V, Toskin I, Festin MP, Gertiser L, Idris R, et al. E-learning for research capacity strengthening in sexual and reproductive health: The experience of the Geneva Foundation for Medical Education and Research and the Department of Reproductive Health and Research, World Health Organization. Hum Resour Health 2016;14:76.  Back to cited text no. 1
    
2.
Guttmacher Institute. Adding it up: Investing in Contraception and Maternal and Newborn Health; 2017. Available from: https://www.guttmacher.org/fact-sheet/adding-it-up-contraception-mnh -2017#seenote. [Last accessed on 2018 Oct 08].  Back to cited text no. 2
    
3.
Singh S, Shekhar C, Acharya R, Moore A, Stillman M, Pradhan M, et al. The incidence of abortion and unintended pregnancy in India, 2015. Lancet Glob Health 2018;6:e111-20.  Back to cited text no. 3
    
4.
World Health Organization. Emergency Contraception. Available from: https://www.who.int/news-room/fact-sheets/detail/emergency -contraception. [Last accessed on 2018 Nov 06].  Back to cited text no. 4
    
5.
Government of Punjab Department of Health & Family Welfare. National Family Welfare Programme. Available from: http://pbhealth.gov.in/pdf/FW.pdf. [Last accessed on 2018 Sep 10].  Back to cited text no. 5
    
6.
National Health Mission Department of Health and Family Welfare. Essential Drugs List. Available from: http://nrhmhp.gov.in/sites/defa ult/files/files/List%20of%20EDL(2).pdf. [Last accessed on 2018 Sep 10].  Back to cited text no. 6
    
7.
National Health Mission Ministry of Health and Family Welfare. List of Drugs Being Provided in ASHA kit. Available from: https://nhm.gov.in/index1.ph p?lang=1&level=2&sublinki d=177&lid=250. [Last accessed on 2018 Sep 10].  Back to cited text no. 7
    
8.
Dixit A, Khan ME, Bhatnagar I. Mainstreaming of emergency contraception pill in India: Challenges and opportunities. Indian J Community Med 2015;40:49-55.  Back to cited text no. 8
[PUBMED]  [Full text]  
9.
Kishore V, Misro MM, Nandan D. Providers' knowledge, attitude and dispensing practices of e-pills in government dispensaries of South district in delhi, India. Indian J Community Med 2010;35:46-51.  Back to cited text no. 9
[PUBMED]  [Full text]  
10.
Saxena P, Mishra A, Nigam A. Evaluation of pharmacists' services for dispensing emergency contraceptive pills in Delhi, India: A mystery shopper study. Indian J Community Med 2016;41:198-202.  Back to cited text no. 10
[PUBMED]  [Full text]  
11.
International Institute for Population Sciences. National Family Health Survey (NFHS-4), 2016-16. Available from: http://rchiips.org/NFHS/NFHS-4Re ports/India.pdf. [Last accessed on 2018 Sep 10].  Back to cited text no. 11
    
12.
Takkar N, Goel P, Saha PK, Dua D. Contraceptive practices and awareness of emergency contraception in educated working women. Indian J Med Sci 2005;59:143-9.  Back to cited text no. 12
[PUBMED]  [Full text]  
13.
Kumar M, Meena J, Sharma S, Poddar A, Dhalliwal V, Modi S, Singh K. Contraceptive use among low-income married women in India. J Sex Med 2010;8:376-82.  Back to cited text no. 13
    
14.
Kapoor R, Patel M, Nayak H. A study on knowledge and use of emergency contraceptive pills among female sex workers of Ahmedabad. Natl J Community Med 2018;9:764-8.  Back to cited text no. 14
    
15.
Harne P, Khan A. Awareness and usage of emergency contraceptive pills among working women: a hospital based survey from north India. Int J Reprod Contracept Obstet Gynecol 2016;5:1202-1206.  Back to cited text no. 15
    
16.
Chopra S, Dhaliwal L. Knowledge, attitude and practices of contraception in urban population of North India. Arch Gynecol Obstet 2010;281:273-7.  Back to cited text no. 16
    
17.
Sen G, Ostlin P. Gender inequity in health: Why it exists and how we can change it. Glob Public Health 2008;3 Suppl 1:1-2.  Back to cited text no. 17
    
18.
Hawkes S, Buse K. Gender and global health: Evidence, policy, and inconvenient truths. Lancet 2013;381:1783-7.  Back to cited text no. 18
    
19.
Stroup DF1, Berlin JA, Morton SC, Olkin I, Williamson GD, Rennie D, et al. Meta-analysis of observational studies in epidemiology (MOOSE) group. Meta-analysis of observational studies in epidemiology: A proposal for reporting. JAMA 2000;283:2008-12.  Back to cited text no. 19
    
20.
Herzog R, Alvarez-Pasquin M, Diaz C, Barrio J, Estrada J, Gil A. Are healthcare workers' intentions to vaccinate related to their knowledge, beliefs and attitudes? A systematic review. BMC Public Health 2013;13:154.  Back to cited text no. 20
    
21.
Newcastle-Ottawa Quality Assessment form for Cohort Studies. Available from: http://file:///C:/Users/Administrator/Dow nloads/appe-fm3%20(3).pdf. [Last accessed on 2018 Dec 19].  Back to cited text no. 21
    
22.
Chin-Quee D, L'Engle K, Otterness C, Mercer S, Chen M. Repeat use of emergency contraceptive pills in urban Kenya and Nigeria. Int Perspect Sex Reprod Health 2014;40:127-34.  Back to cited text no. 22
    
23.
Weinberg F, Kadri S. Contraceptive devices in India. Global J Med Public Health 2014;3. Available from: http://www.gjmedph.com/upl oads/R2-Vo3No6.pdf. [Last accessed on 2019 Mar 22].  Back to cited text no. 23
    
24.
Mir AS, Malik R. Emergency contraceptive pills: Exploring the knowledge and attitudes of community health workers in a developing Muslim country. N Am J Med Sci 2010;2:359-64.  Back to cited text no. 24
    
25.
Shoveller J, Chabot C, Soon J, Levine M. Identifying barriers to emergency contraception use among young women from various sociocultural groups in British Columbia, Canada. Perspect Sex Rep Health 2007;39:13-20.  Back to cited text no. 25
    
26.
Raine TR, Harper CC, Rocca CH. Direct access to emergency contraception through pharmacies and effect on unintended pregnancy and STIs: A randomised controlled trial. JAMA 2005;293:54-62.  Back to cited text no. 26
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2]



 

Top
 
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
    Abstract
   Introduction
    Materials and Me...
   Results
   Discussion
   Conclusion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed401    
    Printed7    
    Emailed0    
    PDF Downloaded110    
    Comments [Add]    

Recommend this journal