Dataset Information

Parity and the risks of adverse birth outcomes: a retrospective study among Chinese.

ABSTRACT:

Background

Nulliparity is considered to be a risk factor of preterm birth (PTB), low birth weight (LBW) and small for gestational age (SGA). With the new two-child policy launched in 2016, more Chinese women have delivered their 2nd baby. Yet few studies have assessed the impact of parity on adverse birth outcomes in China. This study aimed to examine the association between parity and risks of PTB, LBW and SGA in a Chinese population. The combined effects of maternal age and parity on adverse birth outcomes were also assessed.

Methods

This retrospective study included all non-malformed live births born during January 1, 2014 and December 31, 2018 in Chengdu, China. A total of 746,410 eligible live singletons with complete information were included in the analysis. Parity was classified into nulliparity (i.e. has never delivered a newborn before) and multiparity (i.e. has delivered at least one newborn before). Log-binomial regression analyses were applied to evaluate the association between parity and PTB, LBW and SGA. We further divided maternal age into different groups (< 25 years, 25-29 years, 30-34 years and ≥ 35 years) to assess the combined effects of maternal age and parity on adverse birth outcomes.

Results

Multiparity was associated with reduced risks of PTB (aRR = 0.91, 95% CI: 0.89-0.93), LBW (aRR = 0.74, 95% CI: 0.72-0.77) and SGA (aRR = 0.67, 95% CI: 0.66-0.69) compared with nulliparity. In each age group, we observed that multiparity was associated with lower risks of adverse birth outcomes. Compared to nulliparous women aged between 25 and 29 years, women aged ≥35 years had greater risks of PTB and LBW, regardless of their parity status. In contrast, multiparous women aged ≥35 years (aRR = 0.73, 95% CI: 0.70-0.77) and those aged < 25 years (aRR = 0.88, 95% CI: 0.84-0.93) were at lower risk of SGA compared with nulliparous women aged between 25 and 29 years.

Conclusion

Multiparity was associated with lower risks of all adverse birth outcomes. Special attention should be paid to nulliparous mothers and those with advanced age during antenatal care, in order to reduce the risks of adverse birth outcomes.

SUBMITTER: Lin L

PROVIDER: S-EPMC8004392 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:ObjectiveTo re-evaluate the causal effect of interpregnancy interval on adverse birth outcomes, on the basis that previous studies relying on between mother comparisons may have inadequately adjusted for confounding by maternal risk factors.DesignRetrospective cohort study using conditional logistic regression (matching two intervals per mother so each mother acts as her own control) to model the incidence of adverse birth outcomes as a function of interpregnancy interval; additional unconditional logistic regression with adjustment for confounders enabled comparison with the unmatched design of previous studies.SettingPerth, Western Australia, 1980-2010.Participants40 441 mothers who each delivered three liveborn singleton neonates.Main outcome measuresPreterm birth (<37 weeks), small for gestational age birth (<10th centile of birth weight by sex and gestational age), and low birth weight (<2500 g).ResultsWithin mother analysis of interpregnancy intervals indicated a much weaker effect of short intervals on the odds of preterm birth and low birth weight compared with estimates generated using a traditional between mother analysis. The traditional unmatched design estimated an adjusted odds ratio for an interpregnancy interval of 0-5 months (relative to the reference category of 18-23 months) of 1.41 (95% confidence interval 1.31 to 1.51) for preterm birth, 1.26 (1.15 to 1.37) for low birth weight, and 0.98 (0.92 to 1.06) for small for gestational age birth. In comparison, the matched design showed a much weaker effect of short interpregnancy interval on preterm birth (odds ratio 1.07, 0.86 to 1.34) and low birth weight (1.03, 0.79 to 1.34), and the effect for small for gestational age birth remained small (1.08, 0.87 to 1.34). Both the unmatched and matched models estimated a high odds of small for gestational age birth and low birth weight for long interpregnancy intervals (longer than 59 months), but the estimated effect of long interpregnancy intervals on the odds of preterm birth was much weaker in the matched model than in the unmatched model.ConclusionThis study questions the causal effect of short interpregnancy intervals on adverse birth outcomes and points to the possibility of unmeasured or inadequately specified maternal factors in previous studies.

Project description:ObjectiveTo clarify high-risk factors for adverse pregnancy outcomes (APOs) in systemic lupus erythaematosus (SLE).DesignA retrospective chart review study.SettingData were collected in a tertiary medical centre, Shanghai, China, from November 2010 to December 2018.ParticipantsA total of 513 pregnancies with SLE were retrospectively analysed. Twenty-seven patients who underwent artificial abortions due to personal reasons were excluded.Primary outcome measuresAPOs were primary outcomes, including foetal loss, premature birth, small for gestational age (SGA), asphyxia neonatorum, composite foetal APOs and hypertensive disorders of pregnancy (HDP). Multivariable logistic regression and Spearman correlation analysis were performed to determine the risk factors for APOs in SLE.ResultsRisk factors for foetal loss included prepregnancy hypertension, hypocomplementaemia-C3, anticardiolipin antibodies-IgM positivity and disease flares during pregnancy. Risk factors for premature birth included disease flares, use of immunosuppressive agents and HDP. Moreover, twin pregnancy, disease flares and HDP were risk factors for SGA, and prepregnancy hypertension was an independent risk factor for asphyxia neonatorum. Independent risk factors for composite foetal APOs included twin pregnancy, prepregnancy hypertension, disease flares during pregnancy, HDP, hypocomplementaemia-C3 and the use of immunosuppressive agents. Risk factors for SLE complicated with HDP included prepregnancy hypertension, renal disorders and thrombocytopaenia. Conversely, the use of aspirin was a protective factor against foetal loss and premature birth. The ds-DNA value had a low diagnostic value for APOs, whereas the extent of complement reduction may predict the incidence of composite foetal APOs and foetal loss. Proteinuria occurring in the first 20 gestational weeks may lead to APOs.ConclusionEstablished risk factors for each APO were identified in this study. Indicators with more predictive significance have been screened out from conventional indicators, which may help clinicians predict the pregnancy outcome of patients with SLE more accurately and minimise the incidence of APOs.