Effects of nifedipine on doppler indices of fetal middle cerebral artery and umbilical artery in managing hypertensive disorders of pregnancy.
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Date
2020
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Authorea Preprints.
Abstract
Background: Hypertensive disorders of pregnancy affects almost 6 percent of all pregnancies
all over the world with recent statistical data showing an increase of incidence rates both in the
developed and developing worlds. HDP affects uteroplacental and fetoplacental perfusion and
may result into poor fetal conditions and increase morbidity and mortality. Calcium channel
blockers (CCB) are the most commonly used antihypertensive oral medications in pregnancy
due to effectiveness and less side effects.
Aim: To study how effective CCB are in improving uteroplacental perfusion and as to study
whether lowering of blood pressure by CCB may have positive or negative impact to Doppler
indices of fetal middle cerebral artery (MCA) as well as umbilical artery (UA) S/D which were
measure by Doppler indices variables which include MCA peak systolic velocity (PS), MCA
pulsatility index (PI), MCA resistance index (RI) and UA systolic to diastolic ratio (S/D).
Material and methodology: the study involved one hundred and twenty pregnant women with
the gestation ages ranging from thirty-two weeks to forty weeks. Among them sixty were
having hypertensive disorders of pregnancy including preeclampsia and sixty were normal
pregnant women. In case groups blood pressure before and after at least one of medication
were recorded, and Doppler ultrasound indices for fetal MCA and UA S/D after at least one
week of medication was also recorded, follow up for calcium channel blocker dosage was
recorded, delivery gestation age, mode of delivery and Apgar score, as well as neonate
hospitalization was also recorded. In the control group, blood pressure, fetal MCA indices and
UA S/D, delivery gestation age, mode and Apgar score were and related.
Results: We analyzed the results by using statistical package for social sciences (SPSS) version
20, in which Doppler indices between the case and control groups were compared. MCA Peak
systolic speed, UA S/D ratio, MCA Pulsatile index and MCA resistance index mean values
differences between the two groups were not statistically significant i.e. p-value >0.05 (p-
value=0.68,0.062,0.18,0.115 respectively). However, in comparing resistance index (RI)
between case group nifedipine users of 30mg dose per day with control group p-value was
statistically significant (p-value=0.026, 95% CI =-011 to-0.007). In correlation with p-
value<0.05,and measured by (coefficient b±SE): PS was affected by gestation age
(b±SE=1.63±0.42) , S/D ratio was affected by gestation age(b±SE=-01±0.02), systolic blood
pressure (b±SE=0.013±0.004) and age of women (b±SE=0.007±0.013), PI on the other hand
was impacted by gravidity(b±SE=0.07±0.03) and preeclampsia(b±SE=0.2±0.07). RI showed
correlation with chronic hypertension (b±SE=-0.08±0.03). on outcomes of pregnancy there
was a relationship between S/D and Apgar score, an increase of S/D was associated with
decrease of Apgar score, b±SE=-0.16±0.06,95% CI=-0.27 to 0.05, p-value=0.06. Apgar
score≥8 in the control group was 52(86.7%) compared to 60(100%) in the control group. Apgar
score 6-7 was 7(11.7%) in case group compared to 0(0%) in control group. There was one case
1(1.6%) with Apgar score<6 in cases group comparing to 0(0%) in controls.
Conclusion: Apart from having good effect in lowering blood pressure and having less
teratogenic effects, oral use of nifedipine as an antihypertensive of choice in managing
hypertensive disorders of pregnancy seem to improve uteroplacental perfusion in women with
hypertensive disorders of pregnancy . Even with the use of CCB women with HDP had a high
need for early termination of pregnancy compared to normotensive women . We also found
out that low dose of nifedipine (30mg per day) in cases especially with preeclampsia was
associated with a significantly high RI compared to those using high dose of nifedipine.
Description
Keywords
Doppler indices, Middle cerebral artery, Pregnancy
Citation
Kizwi, H., Zhu, J., Magesa, M., Wu, M. and Salum, S., 2020. Effects of nifedipine on doppler indices of fetal middle cerebral artery and umbilical artery in managing hypertensive disorders of pregnancy. Authorea Preprints.