Achieving Lower Preterm Birth Rates in China via Reductions in Iatrogenic Preterm Births

Association of interpregnancy interval and risk of adverse pregnancy outcomes in woman by different previous gestational ages

BACKGROUND

With an increasing proportion of multiparas, proper interpregnancy intervals (IPIs) are urgently needed. However, the association between IPIs and adverse perinatal outcomes has always been debated. This study aimed to explore the association between IPIs and adverse outcomes in different fertility policy periods and for different previous gestational ages.

METHODS

We used individual data from China's National Maternal Near Miss Surveillance System between 2014 and 2019. Multivariable Poisson models with restricted cubic splines were used. Each adverse outcome was analyzed separately in the overall model and stratified models. The stratified models included different categories of fertility policy periods (2014-2015, 2016-2017, and 2018-2019) and infant gestational age in previous pregnancy (<28 weeks, 28-36 weeks, and ≥37 weeks).

RESULTS

There were 781,731 pregnancies enrolled in this study. A short IPI (≤6 months) was associated with an increased risk of preterm birth (OR [95% CI]: 1.63 [1.55, 1.71] for vaginal delivery [VD] and 1.10 [1.03, 1.19] for cesarean section [CS]), low Apgar scores and small for gestational age (SGA), and a decreased risk of diabetes mellitus in pregnancy, preeclampsia or eclampsia, and gestational hypertension. A long IPI (≥60 months) was associated with an increased risk of preterm birth (OR [95% CI]: 1.18 [1.11, 1.26] for VD and 1.39 [1.32, 1.47] for CS), placenta previa, postpartum hemorrhage, diabetes mellitus in pregnancy, preeclampsia or eclampsia, and gestational hypertension. Fertility policy changes had little effect on the association of IPIs and adverse maternal and neonatal outcomes. The estimated risk of preterm birth, low Apgar scores, SGA, diabetes mellitus in pregnancy, and gestational hypertension was more profound among women with previous term births than among those with preterm births or pregnancy loss.

CONCLUSION

For pregnant women with shorter or longer IPIs, more targeted health care measures during pregnancy should be formulated according to infant gestational age in previous pregnancy.

Iatrogenic factors contributed to the high rate of preterm birth in a community hospital

BACKGROUND

Preterm birth (PTB) rates have been increased significantly in recent years, mostly due to obstetric intervention. This study presents the incidence of PTB in community hospitals by assessing the association between pregnancy complications and iatrogenic PTB.

METHODS

A total of 6,693 pregnancies were enrolled in the Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University. They were divided into two groups (<35 and ≥35 years of age) to examine the effect of maternal age on PTB. Binary logistic and multiple linear regression analyses were used to assess the relationship between PTB and pregnancy complications.

RESULTS

This study provided the incidence of PTB and found that PP, PROM, and ICP increased the risk of PTB, indicating that pregnancy complications have led to the iatrogenic PTB and contributed to the high rate of PTB, especially in the group of advanced-age pregnant women. The prevalence of PTB was 9.53%. Placenta previa (PP), premature rupture of membranes (PROM), and intrahepatic cholestasis of pregnancy (ICP) were significantly associated with PTB. Among all the risk factors, hypertension, disease in pregnancy, premature PROM, and PP were observed as independent key factors for iatrogenic PTBs. In the advanced-age group, PP and pPROM increased the risk of PTB.

CONCLUSIONS

It is often necessary to terminate a pregnancy in community hospitals to balance the safety of the fetus and the maternal comorbid symptoms, which has led to nosocomial premature delivery. Therefore, high-risk pregnancies should be carefully evaluated and comprehensively treated with caution to balance the preterm rate and the safety of the pregnant woman and fetus, and the pros and cons of the outcomes, which has brought a challenge to an obstetrician to reduce the proportion of iatrogenic PTB.

FIGO good practice recommendations on modifiable causes of iatrogenic preterm birth

Iatrogenic preterm birth is a planned delivery that occurs before 37 weeks of gestation due to maternal and/or fetal causes. However, in some cases, such deliveries also occur with no apparent medical indication. The increasing numbers of iatrogenic preterm deliveries worldwide have led researchers to identify modifiable causes that allow the formulation of preventive strategies that could impact the overall preterm birth rate. The present document contains the FIGO (International Federation of Gynecology and Obstetrics) Working Group for Preterm Birth recommendations, aiming to reduce the rates of iatrogenic preterm birth based on four of the most common clinical scenarios and issues related to iatrogenic preterm delivery. The working group supports efforts to identify the contribution of iatrogenic preterm delivery to the overall preterm birth rate and encourages health authorities to establish preventive measures accordingly. We encourage care providers to maintain single embryo transfer policies to prevent multiple pregnancies as a substantial contributor of iatrogenic preterm birth. The working group also recommends that efforts to reduce unnecessary cesarean sections must be warranted, and mechanisms to ensure the appropriate time of delivery and strengthening of education and communication processes must be pursued.

Iatrogenic preterm birth contributes substantially to preterm birth rates globally and can be mitigated by identifying modifiable factors and formulating and supporting preventive strategies.

[A multicenter study of the birth condition of preterm infants and the causes of preterm birth in Henan Province, China]

OBJECTIVE

To investigate the birth condition of preterm infants and the causes of preterm birth in Henan Province, China, and to provide a basis for the prevention and treatment of preterm birth.

METHODS

An epidemiological investigation was conducted for live-birth preterm infants who were born in 53 hospitals in 17 cities of Henan Province from January 1, 2019 to December 31, 2019 to investigate the incidence rate of preterm birth, the distribution of gestational age and birth weight, the use of antenatal glucocorticoids, and the causes of preterm birth.

RESULTS

The incidence rate of preterm birth was 5.84% (12 406/212 438) in the 53 hospitals. The proportions of preterm infants with gestational ages of < 28 weeks, 28 - < 32 weeks, 32 - < 34 weeks, and 34 - < 37 weeks were 1.58% (196/12 406), 11.46% (1 422/12 406), 15.18% (1 883/12 406), and 71.78% (8 905/12 406) respectively. The proportions of preterm infants with birth weights of < 1 000 g, 1 000- < 1 500 g, 1 500- < 2 500 g, 2 500- < 4 000 g, and ≥ 4 000 g were 1.95% (240/12 313), 8.54% (1 051/12 313), 49.53% (6 099/12 313), 39.59% (4 875/12 313), and 0.39% (48/12 313) respectively. The infants born by natural labor accounted for 28.76% (3 568/12 406), and those born by cesarean section accounted for 70.38% (8 731/12 406). The rate of use of antenatal glucocorticoids was 52.52% (6 293/11 983) for preterm infants and 68.69% (2 319/3 376) for the preterm infants with a gestational age of < 34 weeks. Iatrogenic preterm labor was the leading cause of preterm birth[40.06% (4 915/12 270)], followed by spontaneous preterm birth[30.16% (3 701/12 270)] and preterm birth due to premature rupture of membranes[29.78% (3 654/12 270)]. The top three causes of iatrogenic preterm birth were hypertensive disorders of pregnancy[47.12% (2 316/4 915)], fetal intrauterine distress[22.85% (1 123/4 915)], and placenta previa/placental abruption[18.07% (888/4 915)].

CONCLUSIONS

There is a relatively low incidence rate of preterm birth in Henan Province, and late preterm infants account for a relatively high proportion. Iatrogenic preterm birth is the main cause of preterm birth in Henan Province, and hypertensive disorders of pregnancy and fetal intrauterine distress are the main causes of iatrogenic preterm birth.

[A multicenter study of the birth condition of preterm infants and the causes of preterm birth in Henan Province, China]

OBJECTIVE

To investigate the birth condition of preterm infants and the causes of preterm birth in Henan Province, China, and to provide a basis for the prevention and treatment of preterm birth.

METHODS

An epidemiological investigation was conducted for live-birth preterm infants who were born in 53 hospitals in 17 cities of Henan Province from January 1, 2019 to December 31, 2019 to investigate the incidence rate of preterm birth, the distribution of gestational age and birth weight, the use of antenatal glucocorticoids, and the causes of preterm birth.

RESULTS

The incidence rate of preterm birth was 5.84% (12 406/212 438) in the 53 hospitals. The proportions of preterm infants with gestational ages of < 28 weeks, 28 - < 32 weeks, 32 - < 34 weeks, and 34 - < 37 weeks were 1.58% (196/12 406), 11.46% (1 422/12 406), 15.18% (1 883/12 406), and 71.78% (8 905/12 406) respectively. The proportions of preterm infants with birth weights of < 1 000 g, 1 000- < 1 500 g, 1 500- < 2 500 g, 2 500- < 4 000 g, and ≥ 4 000 g were 1.95% (240/12 313), 8.54% (1 051/12 313), 49.53% (6 099/12 313), 39.59% (4 875/12 313), and 0.39% (48/12 313) respectively. The infants born by natural labor accounted for 28.76% (3 568/12 406), and those born by cesarean section accounted for 70.38% (8 731/12 406). The rate of use of antenatal glucocorticoids was 52.52% (6 293/11 983) for preterm infants and 68.69% (2 319/3 376) for the preterm infants with a gestational age of < 34 weeks. Iatrogenic preterm labor was the leading cause of preterm birth[40.06% (4 915/12 270)], followed by spontaneous preterm birth[30.16% (3 701/12 270)] and preterm birth due to premature rupture of membranes[29.78% (3 654/12 270)]. The top three causes of iatrogenic preterm birth were hypertensive disorders of pregnancy[47.12% (2 316/4 915)], fetal intrauterine distress[22.85% (1 123/4 915)], and placenta previa/placental abruption[18.07% (888/4 915)].

CONCLUSIONS

There is a relatively low incidence rate of preterm birth in Henan Province, and late preterm infants account for a relatively high proportion. Iatrogenic preterm birth is the main cause of preterm birth in Henan Province, and hypertensive disorders of pregnancy and fetal intrauterine distress are the main causes of iatrogenic preterm birth.

Ten-year time trends in preterm birth during a sociodemographic transition period: a retrospective cohort study in Shenzhen, China

OBJECTIVES

To investigate time trends of preterm birth and estimate the contributions of risk factors to the changes in preterm birth rates over a decade (2009-2018) of transitional period in Shenzhen, China.

DESIGN

Retrospective cohort study between 2009 and 2018.

SETTING

All births in Baoan during January 2009 and December 2018 registered in the Shenzhen Birth Registry Database.

PARTICIPANTS

478 044 live births were included with sociodemographic and medical records for both women and infants.

OUTCOME MEASURES

The incidence rate of preterm birth stratified by different maternal and infant characteristics. Multiple logistic regression was used to identify significant risk factors associated with preterm birth. The population attributable risk fraction of each factor was calculated to estimate its contribution to variations of preterm birth rate over the 10 years.

RESULTS

A total of 27 829 preterm births from 478 044 (5.8%) live births were recorded and the preterm birth rate increased from 5.5% in 2009 to 6.2% in 2018. Medically induced preterm birth rate increased from 2.0% in 2009 to 3.4% in 2018 while spontaneous preterm labour rate decreased from 3.3% to 2.7% over the decade years. Risk factors including multiple pregnancy (0.28% increase) drove the rise of preterm birth rate, whereas changes in maternal educational attainment (0.22% reduction) and prenatal care utilisation (0.45% reduction) had contributed to the decline in preterm birth rate.

CONCLUSIONS

An uptrend of preterm birth rate was observed in an area under rapid sociodemographic transitions during 2009-2018 and the changes were associated with these sociodemographic transitions. Continued investments in girls' education and prenatal care have the potential of reducing preterm birth rate.

Perfluoroalkyl substances exposure in early pregnancy and preterm birth in singleton pregnancies: a prospective cohort study

BACKGROUND

Preterm birth (PTB, < 37 completed weeks' gestation) is one of the global public health concerns. Epidemiologic evidence on the potential impact of perfluoroalkyl substances (PFAS) on PTB is still limited and inconsistent. We aimed to investigate the associations between prenatal PFAS exposure and PTB among singleton live births.

METHODS

We studied 2849 mother-infant pairs in the Shanghai Birth Cohort (SBC) from 2013 to 2016. Ten PFAS in maternal plasma in early pregnancy (gestational age, median (interquartile range): 15 (13-16) weeks) were measured. Primary outcomes were duration of gestation, PTB, spontaneous PTB and clinically indicated PTB. A linear regression model was used to assess the associations between ln-transformed PFAS and duration of gestation (in weeks). Logistic regression models were applied to estimate the relative risks of these outcomes.

RESULTS

The incidence of overall PTB was 4.8% (95% confidence limit: 4.0-5.6%, n = 136) in this study population. In the linear regression analyses, PFAS were not associated with the duration of gestation after controlling for potential confounders. In the multiple logistic models, no significant associations were observed between PFAS and overall PTB, spontaneous or indicated PTB.

CONCLUSION

In this prospective cohort study, we did not observe significant associations between maternal plasma PFAS concentrations in early pregnancy and gestational length, overall PTB, spontaneous or indicated PTB.