Modeling the Distribution of First Birth Interval among Indian Women Using NFHS-4 Data: A Modified Exponential Approach

Anushri P Patil; Mayank Singh; Naresh Kumar Tyagi; Alex M Carvalho; Abhijeet B Shitole

doi:10.55489/njcm.170720266210

Authors

Anushri P Patil Department of Biostatistics and Epidemiology, KLE Academy of Higher Education and Research (KAHER), Deemed to-be University, Belagavi, Karnataka, India https://orcid.org/0000-0002-8263-7667
Mayank Singh Department of Biostatistics and Epidemiology, KLE Academy of Higher Education and Research (KAHER), Deemed to-be University, Belagavi, Karnataka, India https://orcid.org/0000-0002-5350-6895
Naresh Kumar Tyagi Department of Biostatistics and Epidemiology, KLE Academy of Higher Education and Research (KAHER), Deemed to-be University, Belagavi, Karnataka, India https://orcid.org/0009-0005-7203-0203
Alex M Carvalho Department of Biostatistics and Epidemiology, KLE Academy of Higher Education and Research (KAHER), Deemed to-be University, Belagavi, Karnataka, India https://orcid.org/0000-0003-1170-0136
Abhijeet B Shitole Department of Cardiac Anaesthesia, Jawaharlal Nehru Medical College, KLE Academy of Higher Education and Research (Deemed to-be University), Belagavi, Karnataka, India https://orcid.org/0000-0001-5982-618X

DOI:

https://doi.org/10.55489/njcm.170720266210

Keywords:

First Birth Interval, Age at Marriage, Positive skewed distribution, Level of Skewness, Exponential model, NFHS-4

Abstract

Background: The time between marriage and the first childbirth affects population composition, fertility dynamics, maternal and child health, and population policy. This study examines distribution of FBI among Indian women considering its sociodemographic variables. The analysis employs the parameters Mode and Median to study the positive skewed outcome distributions.

Statistical Methods: The distribution of FBI in the sociodemographic variables of Indian women with one child during survey was taken into consideration. The National Family Health Survey-4 is the source of the data. Using the median and mode as distributional parameters, a "Modified exponential model" was developed to assess the degree of FBI skewness across important sociodemographic variables. Log-rank test was used to check the significancy of FBI across maternal sociodemographic variables.

Results: Within 32 months of marriage, 60% of women gave birth to their first child. With a mode of 10 months, the overall median FBI was 28 months. With skewed parameters Mode and Median, the proposed exponential model explained 81.7% variation in the FBI (p<0.001) using age at marriage, place of residence, religion, educational attainment, wealth index, BMI, thyroid disorder status, use of any form of contraception and history of pregnancy termination as significant predictors.

Conclusion: The modified exponential model can assist health care providers and stakeholders in deciding on a treatment strategy and plan of action to start a woman's reproductive life by indicating expected FBI and skewness. This model can enhance fertility trends in certain socio-demographic, cultural, educational, and geographical female population groups in India.

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