Interpregnancy interval and pregnancy loss in a rural South Africa: A population-based cohort study

ABSTRACT Study question What is the relationship between interpregnancy interval (IPI) and pregnancy loss in a a rural sub-Saharan African (SSA) setting? Summary answer IPIs >60 months, but not <6 months, were associated with a higher odds of pregnancy loss in our SSA setting. What is known already IPIs >60 months are detrimental to both fetal and maternal health, while contradictory findings exist for IPIs <6 months. No studies have investigated the relationship between IPI and pregnancy loss in SSA settings, despite high pregnancy loss rates and exponential population growth in the SSA region. Study design, size, duration Population-based cohort involving 8940 women aged 16-35 years who reported two consecutive singleton pregnancies between 2000 and 2017. Participants/materials, setting, methods Study participants were from the uMkhanyakude District in KwaZulu-Natal, South Africa. We obtained data on pregnancy-related characteristics and other variables relevant to pregnancy loss from regular surveys conducted by the Africa Health Research Institute (AHRI) as part of its demographic and health surveillance platform. IPI was determined as the time in months between the end of the first pregnancy and the start of the second pregnancy. Pregnancy loss was defined as either miscarriage or stillbirth. We used an adjusted logistic regression model to investigate the relationship between IPI and pregnancy loss. Main results and the role of chance IPIs >60 months were associated with an almost three-fold higher odds of pregnancy loss (Adjusted Odds Ratio: 2.64, 95% Confidence Interval:1.71-4.09) when compared with IPIs of 6-60 months. IPIs <6 months conferred a similar odds of pregnancy loss when compared with IPIs of 6-60 months (Adjusted Odds Ratio: 0.82, 95% Confidence Interval: 0.35-1.91). Limitations, reasons for caution Possible recall bias around some of the pregnancy-related data. Inability to adjust our multivariate statistical analysis for certain sexually transmitted diseases which are known risk factors for pregnancy loss. Wider implications of the findings Family planning services in SSA should consider discouraging IPIs >60 months. Although IPIs <6 months had no impact on pregnancy loss, these should also be discouraged in SSA, given the potential socioeconomic consequences for the already vulnerable women of this region. Study funding/competing interest(s) The corresponding author was supported with a postdoctoral fellowship under a National Institute of Health grant (R01 HD084233). The AHRI demographic and health surveillance platform is supported by the Wellcome Trust (201433/Z/16/Z), and the South African Population Research Infrastructure Network. No competing interests are declared. Trial registration number N/A.