Characteristics of women who dropped out from pregnancy register in Okinawa, Japan: Findings from a retrospective cohort study

Abstract

Aim: There is little evidence regarding women who cannot register live births after pregnancy. We aimed to clarify the difference in baseline characteristics between women who registered live births and those who did not (i.e., dropout). Methods: We assessed the birth cohort data of 1976 Japanese women who registered their pregnancies between July 2013 and March 2014 in Naha and Urasoe City, Okinawa, Japan. The database consisted of anthropometric data, reproductive history, sociodemographic characteristics, and dietary intake. We estimated the prevalence ratio to examine the associations of baseline characteristics with dropout by multivariable-adjusted Poisson regression with robust standard error estimation. Results: We identified 272 dropouts (13.8%) in the pregnancy registry. About 15% of women reported experience of alcohol drinking preceding 1 month of pregnancy registration. Most participants' vitamin B1 (92.1%) and folate (74.7%) consumption was inadequate considering the dietary reference intake for Japanese pregnant women, but it was not associated with a high prevalence of dropout. The prevalence of dropout was significantly higher in teenagers (prevalence ratio [PR] = 2.06, 95% confidence interval [CI] 1.38-3.07) and early 20s (PR = 1.42, 95% CI 1.04-1.93) than in women in late 20s. In addition, alcohol consumption was potentially associated with a high prevalence of dropout (adjusted prevalence ratio [aPR] = 1.31, 95% CI 0.99-1.73). Participants who experienced one or more live births (aPR = 0.43, 95% CI 0.28-0.66) were less likely to dropout. Conclusion: We found that the potential risk factors for dropout from pregnancy registration were young maternal age, no childbirth experience, and alcohol consumption.