Dr Fergus McCarthy takes a monthly look at articles just published in the area of hypertension & pre-eclampsia:  

Magro-Malosso et al published their systematic review and meta-analysis examining associations between exercise during pregnancy and risk of gestational hypertensive disorders.¹ The meta- analysis included seventeen trials including 5,075 pregnant women of which seven were included in the quantitative meta-analysis for the primary outcome. The primary outcome was the incidence of gestational hypertensive disorders, defined as either gestational hypertension or pre-eclampsia. Women who were randomized in early pregnancy to aerobic exercise for about 30-60 minutes 2-7 times per week had a significant lower incidence of gestational hypertensive disorders (5.9% vs 8.5%; RR 0.70, 95% CI 0.53 to 0.83; 7 studies, 2,517 participants), specifically a lower incidence of gestational hypertension (2.5% vs 4.6%; RR 0.54, 95% CI 0.40 to 0.74; 16 studies, 4,641 participants) compared to controls. Interestingly, no significant differences were observed in the incidence of pre-eclampsia (2.3% vs 2.8%; RR 0.79, 95% CI 0.45 to 1.38; 6 studies, 2,230 participants).

The complex interactions between maternal BMI and risk of pre-eclampsia are highlighted by work published by Viera et al on behalf of the SCOPE consortium.² In this they compared risk factors for pre-eclampsia between women with obesity (BMI ≥30 kg/m²) and those with a normal BMI (20-25 kg/m²). Data from 3,940 eligible nulliparous women was analysed including a total of 53 biomarkers of glucose and lipid metabolism, placental function, and known markers of pre-eclampsia. Among 834 women with obesity and 3,106 with a normal BMI, 77 (9.2%) and 105 (3.4%) developed pre-eclampsia, respectively. In women with obesity, risk factors included a family history of thrombotic disease, low plasma placental growth factor, and higher uterine artery resistance index at 20 weeks’ gestation. In contrast, the factors for women with a normal BMI associated with pre-eclampsia included a family history of pre-eclampsia or gestational hypertension, mean arterial blood pressure, plasma endoglin and cystatin C, and uterine artery resistance index.

Following on from our review last month of the long-term cardiovascular complications of pre-eclampsia, Siepmann et al examine the long-term cerebrovascular changes in women with pre-eclampsia by conducting a case-control study in women between 5 and 15 years after either a pre-eclamptic using brain MRI.³ Brain MRI from thirty-four previously pre-eclamptic women and 49 controls was performed and analysed. Previously pre-eclamptic women had reduced cortical gray matter volume (523.2 ± 30.1 vs 544.4 ± 44.7 mL, p≤ 0.05). Women with previous pre-eclampsia also displayed increased temporal lobe white matter disease (lesion volume: 23.2 ± 24.9 vs 10.9 ± 15.0 mL, p ≤ 0.05) and altered microstructural integrity (radial diffusivity: 538 ± 19 vs 526 ± 18 x10^-6 mm²/s, p ≤0.01), which also extended to occipital and parietal lobes. The severity of these changes was in proportion to the time since pregnancy occurred.

Finally, it is hoped in the coming years as ongoing prospective studies yield results that our ability to predict those at highest risk of pre-eclampsia and initiate timely prophylaxis with aspirin will continue to improve. Tan et al recently published their study protocol from the “Screening programme for pre-eclampsia” (SPREE) study.⁴ This study which has recruited 13,000 women as of November 2016 is examining the early prediction of pre-eclampsia by using a novel Bayes-based method that combines maternal characteristics and medical history together with the measurements of mean arterial pressure, uterine artery pulsatility index, serum placental growth factor and pregnancy-associated plasma protein-A at 11-13 weeks’ gestation (referred to as the “combined test”). This combined test can be further simplified to the “mini-combined test” when only maternal factors, MAP and PAPP-A are taken into consideration. The authors hypothesise that the first-trimester mini-combined test and combined test are likely to be superior to the current method recommended by NICE that is based on maternal demographics and history alone.

References

1. Magro-Malosso ER, Saccone G, Di Tommaso M, Roman A, Berghella V. Exercise during pregnancy and risk of gestational hypertensive disorders: a systematic review and meta-analysis. Acta obstetricia et gynecologica Scandinavica. Apr 12 2017.
2. Vieira MC, Poston L, Fyfe E, et al. Clinical and biochemical factors associated with preeclampsia in women with obesity. Obesity. Feb 2017;25(2):460-467.
3. Siepmann T, Boardman H, Bilderbeck A, et al. Long-term cerebral white and gray matter changes after preeclampsia. Neurology. Mar 28 2017;88(13):1256-1264.
4. Tan MY, Koutoulas L, Wright D, Nicolaides KH, Poon LC. A study protocol for the prospective validation study: Screening programme for pre-eclampsia (SPREE). Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology. Mar 13 2017.