Birth and birth-related obstetrical characteristics in southwestern China associated with the current adjustment of family planning policy: a 7-year retrospective study

Abstract

In China, the adjustment of the family planning policy was expected to increase the number of births and trigger a change in the demographic and obstetrical background of pregnant women. The policy itself, and corresponding background variations of the pregnant mothers, might have various influences on certain birth-related characteristics. Moreover, the adaption of the medical system to the policy needs to be demonstrated. To address these issues, over 50,000 individual records from January 2012 to December 2018 were collected from a large tertiary care centre of southwest China as a representative. The monthly numbers of deliveries and births showed stabilized patterns after remarkable upward trends. Policy-sensitive women, among whom older age and multiparity were typical features, contributed considerably to the remarkable additional births. Indeed, multivariable logistic regression analysis identified the child policy and these two background characteristics as factors influencing CS (caesarean section) rate and certain pregnancy complications or adverse outcomes. After the implementation of the two-child policy, a care provider was faced with fewer but more difficult cases. Briefly speaking, more individual-based studies on family planning policy and more efforts to improve obstetrical service are needed to better guide clinical practice in the new era.

Figure 1

Flowchart of the study.

Figure 2

Monthly trends of deliveries and corresponding background of pregnant women (a) The monthly trends of (1) the absolute number of deliveries (gestational age ≧ 28w) (black curve, left axis); (2) the absolute number of abortions or miscarriages (gestational age < 28w) (brown curve, left axis); and (3) the percentage of multiparous mothers (blue curve, right axis). (b) The monthly age constitution of pregnant women. It can be seen as 2 figures. Both the heatmap and the line chart were generated and merged by GraphPad Prism 8 for Windows, Version 8.0.1 (244), URL link: https://www.graphpad.com/. The heatmap shows the detailed distribution of pregnant women of each age: each column represents each month (from year of 2012 to 2018) and each row an age (from 14 to 53 years); the colour, with its colour key at the very right of the figure, indicates the percentage of women of that age among all the delivered mothers in the corresponding month. In the line chart, the X axis (the same as that of the heat map) indicates the time of delivery, while the Y axes (not shown) indicate the percentages of women in the corresponding age groups: (1) lower-age (from 14 to 19 years): a stable curve (ranging from 0 to a peak at 1.21%); (2) right-age (from 20 to 34 years): a declining curve (peak at 91.95% and bottom at 79.89%); (3) advanced-age (35 years or older): an increasing curve (bottom at 7.59% and peak at 19.83%).

Figure 3

Actual births and hypothetical births. The left panel shows births to all pregnant mothers. The upper right shows births to multiparous mothers, while the lower right shows births to older mothers (≧35 years). The curves of actual births are coloured in black and that of hypothetical births in brown. In each panel, the areas between the two curves could be interpreted as additional births attributed to (1) S1 (pink): the selective two-child policy; and (2) S1 + S2 (pink and purple): the monolithic policy change.

Figure 4

Births and care providers. The temporal patterns of: (1) the absolute number of births (black curve, left axis); (2) the absolute number of care providers (brown curve, left axis); and (3) the workload of care providers, shown by the ratio of births to care providers (blue curve, right axis).

Figure 5

The association between maternal age and adverse outcomes. In the line chart, the X axis indicates the maternal age, while the Y axis indicates the incidence of maternal adverse outcomes, shown as a percentage. All maternal adverse outcomes were equally weighted, including PE, ICP, GDM, PP, PA, PTB, PROM, chorioamnionitis, PPH, ICU admittance, and death. Curve A: the numerator is the number of mothers who experienced at least one of the 11 outcomes, and the denominator is the total number of mothers at the corresponding age. Curve B: cumulative outcomes, meaning that the numerator is the total frequency of all 11 outcomes, while the denominator is 11 times the number of mothers.