Department of Obstetrics and Gynecology, Aarhus University Hospital, Aarhus, Denmark.
Perinatal Epidemiology Research Unit, Institute of Clinical Medicine & Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark.
Acta Obstet Gynecol Scand. 2020 May;99(5):623-630. doi: 10.1111/aogs.13786. Epub 2020 Feb 4.
Hypertensive disorders of pregnancy, including gestational hypertension and preeclampsia, are leading causes of morbidity and mortality for both mother and fetus. It has been proposed that vitamin D affects a number of biological processes involved in the pathogenesis of hypertensive disorders of pregnancy. Therefore, a seasonal variation in the risk of these disorders might be expected in areas such as Denmark with marked seasonal variation in sunlight exposure. In this study, we aimed to evaluate the existence of this association.
We used information from a cohort of 50 665 previously healthy, nulliparous women with singleton pregnancies. All women gave birth between 1989 and 2010 at Aarhus University Hospital, Denmark. Logistic regression analyses combined with the cubic spline method were used to estimate the seasonal variation for each outcome: gestational hypertension and preeclampsia, after adjusting for calendar time.
Of the 50 665 women included, 8.5% were diagnosed with a hypertensive disorder of pregnancy. The overall tendency was towards increasing risk when conceiving during spring and early summer, peaking midsummer, and subsequently decreasing steadily during late summer and fall to reach the nadir by winter. Seasonal variation was found for; gestational hypertension (P = .01); preeclampsia (P = .001) and early-onset preeclampsia (P = .014).
We found a seasonal variation in the risk of the hypertensive disorders of pregnancy in a large cohort of Danish nulliparous women. The highest risk was seen in women with the estimated date of conception in June and August, that is, during summer. Seasonal variation in vitamin D status may explain this association.
妊娠高血压疾病，包括妊娠期高血压和子痫前期，是导致母婴发病率和死亡率的主要原因。维生素 D 影响妊娠高血压疾病发病机制中涉及的许多生物学过程，因此，在丹麦等阳光照射季节性变化明显的地区，这些疾病的风险可能会出现季节性变化。本研究旨在评估这种关联是否存在。
我们使用了一个队列的信息，该队列包括 50665 名以前健康、初产妇的单胎妊娠妇女。所有妇女均于 1989 年至 2010 年在丹麦奥胡斯大学医院分娩。采用逻辑回归分析结合三次样条法，在调整了日历时间后，估计每个结局（妊娠期高血压和子痫前期）的季节性变化。
在 50665 名纳入的妇女中，8.5%被诊断为妊娠高血压疾病。总的趋势是在春季和初夏受孕时风险增加，仲夏达到高峰，随后在夏末和秋季稳步下降，到冬季达到最低点。季节变化见于：妊娠期高血压（P=0.01）；子痫前期（P=0.001）和早发型子痫前期（P=0.014）。
我们在一个大型丹麦初产妇队列中发现了妊娠高血压疾病风险的季节性变化。风险最高的是估计受孕日期在 6 月和 8 月的妇女，即夏季。维生素 D 状态的季节性变化可能解释了这种关联。
