Maternal haemodynamic profile in pregnancy after assisted reproductive technology: A pilot study

Singleton pregnancies obtained by assisted reproductive technology (ART) are at increased risk of adverse pregnancy outcome. Aim of this pilot study was to compare maternal hemodynamic profile in ART and spontaneous singleton pregnancies. Patients were enrollered during a third trimester routine obstetric examination. Maternal haemodynamic assessment was carried out by a single trained operator using an UltraSonic Cardiac Output Monitor in standardized conditions. Our pilot data suggests that women conceived after ART may have significantly lower Cardiac Output and significantly higher Systemic Vascular Resistance when compared to those conceiving spontaneously. These differences, if confirmed in larger studies, might explain the increased prevalence of adverse outcome, especially hypertensive disorders of pregnancy, in singleton ART pregnancies.

Can sonographic assessment of pulmonary vascular reactivity following maternal hyperoxygenation predict neonatal pulmonary hypertension? (HOTPOT study protocol)

Background

Persistent pulmonary hypertension of the newborn (PPHN) is a condition that occurs in 0.5–7 per 1000 live births and can result in significant cardiovascular instability in the newborn. It occurs when there is a failure of the normal circulatory transition in the early newborn period. Recent studies have shown that fetal pulmonary vasculature reacts to maternal hyperoxygenation (MH). The aim of the study is to assess if the in-utero response to MH can predict pulmonary hypertension in the early newborn period.

Methods

We will perform a prospective cohort study. It will evaluate the use of fetal echocardiographic Doppler assessment of the pulmonary vasculature prior to and following MH to predict fetuses that may develop pulmonary hypertension in the neonatal period. The study will be undertaken in the Rotunda Hospital, Dublin, Ireland. A fetal ultrasound and echocardiography will be performed on fetuses in the third trimester. Blood flow velocity waveforms will be recorded during periods of fetal quiescence. Pulsatility index (PI), Resistance index (RI), Peak systolic (PSV) and end diastolic velocity (EDV), time-averaged velocity (TAV), acceleration time (AT), and ejection time (ET) will be measured within the fetal distal pulmonary artery (PA). The acceleration-to-ejection time ratio (AT: ET) will be used to assess pulmonary vascular resistance (PVR). Doppler measurements will be taken at baseline and repeated immediately following MH for 10 min (O2 100% v/v inhalational gas) at a rate of 12L/min via a partial non-rebreather mask. Doppler waveform measurements from the umbilical artery (UAD), middle cerebral artery (MCA) ductus arteriosus (DA), aortic isthmus (AoI) and ductus venosus (DV) will also be obtained. After birth, a comprehensive neonatal functional echocardiogram will be performed within the first 24 hours of life.

Discussion

This study proposes to validate methods described to date in investigating the fetal pulmonary vascular response to MH, with expansion of the study subjects to include fetuses at risk of PPHN. Evaluation of the different at-risk subgroups will be informative in relation to the fetal circulatory adaptation close to term. Prediction of neonatal pulmonary hypertension may help guide the pharmacological and neonatal ICU strategies that optimise postnatal survival.

Acute cardiovascular changes in women undergoing in vitro fertilisation (IVF), a systematic review and meta-analysis

OBJECTIVES

Ovarian stimulation during fertility treatment leads to profound maternal physiological changes. Women undergoing in vitro fertilisation (IVF) may be at an increased risk of future cardiovascular morbidity, though little is known about the effects on maternal cardiovascular function. We aim to systematically review whether IVF treatment is associated with changes in maternal haemodynamic parameters, and the effects of different protocols.

STUDY DESIGN

A systematic review and meta-analysis of English language studies identified on Medline and EMBASE database, between 1978, to 2019. Search terms: IVF, maternal haemodynamics, and cardiovascular. Studies reporting on ovulation induction, intrauterine insemination, and oocyte donation were excluded. Methodological quality was assessed by using the adapted Critical Appraisal Skills Programme (CASP) checklist. A meta-analysis was conducted for blood pressure and heart rate on patients undergoing the long GnRH agonist protocol according to Cochrane guidelines. We considered four time points in the IVF cycle, in chronological order: pre-treatment, pituitary down regulation, peak oestradiol and the luteal phase.

RESULTS

Nine suitable studies were identified; four fulfilled the criteria for meta-analysis. Two studies measuring heart rate found a significant increase in heart rate from pituitary down-regulation to peak estradiol levels, which was supported by the meta-analysis (3.78 ± 2.18 (p= < 0.0001)). Three studies reported a significant decrease in blood pressure from baseline, with those suitable for meta-analysis showing a significant decrease in mean arterial pressure (-2.08 ± 1.79 (p= < 0.0001)). Cardiac functional changes were reported for all studies and the changes depended on the type of protocol used.

CONCLUSIONS

In Vitro Fertilisation leads to acute changes in maternal haemodynamics at different time points of the stimulation protocol. We found an increase in heart rate from pituitary down-regulation to peak estradiol levels and a significant decrease in blood pressure from baseline or pituitary down-regulation to the luteal phase. Cardiac functional changes were reported for all studies on the agonist protocol, but no significant changes were found using the antagonist protocol. It remains unclear as to whether these acute changes were associated with pregnancy complications or chronic cardiovascular sequelae.

Peripheral maternal haemodynamics across pregnancy in hypertensive disorders of pregnancy

OBJECTIVES

Evaluating maternal haemodynamics across pregnancy in uncomplicated pregnancies and those complicated by hypertensive disorders of pregnancy (HDP).

STUDY DESIGN

Prospective cohort study from 2015 to 2018 of healthy, nulliparous, singleton-bearing women. Maternal haemodynamics assessed by Uscom BP+ at 9-16 and 32-36 weeks' gestation in pregnancies complicated by HDP [preeclampsia with severe (sPE n = 12) and without severe clinical features (nsPE n = 49), gestational hypertension (GH n = 25), transient gestational hypertension (TGH n = 33)] were compared to uncomplicated pregnancies (n = 286) using mixed-effects linear modelling.

MAIN OUTCOME MEASURES

Maternal haemodynamic adaptation in uncomplicated pregnancies and those complicated by HDP.

RESULTS

Between the two measurements, haemodynamic adaptation in women with sPE and nsPE was significantly different compared to those with uncomplicated pregnancies. An additional increase was observed for peripheral systolic blood pressure [SBP; 14.3 mmHg, 8.6-20.1 (sPE)], peripheral diastolic blood pressure [DBP; 7.7 mmHg, 3.3-12.1 (sPE); 2.6 mmHg, 3.3-12.1 (nsPE)] peripheral mean arterial pressure [MAP; 10.6 mmHg, 5.8-15.5 (sPE); 3.4 mmHg, 0.8-6.0 (nsPE)], peripheral pulse pressure [PP; 6.6 mmHg, 2.1-11.1 (sPE)], central SBP [15.8 mmHg, 10.4-21.2 (sPE); 2.9 mmHg, 0.1-5.8 (nsPE)], central DBP [8.3 mmHg, 3.9-12.6 (sPE); 2.5 mmHg, 0.2-4.8 (nsPE), central MAP [10.8 mmHg, 6.4-15.2 (sPE); 2.6 mmHg, 0.3-5.0 (nsPE)] and central PP [7.6 mmHg, 3.9-11.3 (sPE)]. Augmentation index (AIx) decreased less (15.5%, 6.3-24.6 (sPE); 9.0%, 4.2-13.6 (nsPE)] compared to uncomplicated pregnancies. Haemodynamic adaptation across pregnancy in women with GH and TGH was not different from those with uncomplicated pregnancies.

CONCLUSION

Women who develop preeclampsia show an altered, while those who develop GH or TGH demonstrate a comparable haemodynamic adaptation compared to uncomplicated pregnancies. TGH is not a benign condition.

The Effect of Chorionicity on Maternal Cardiac Adaptation to Uncomplicated Twin Pregnancy: A Prospective Longitudinal Study

OBJECTIVE

The objective of this study was to longitudinally evaluate maternal echocardiographic findings in uncomplicated twin gestations according to chorionicity.

METHODS

Healthy women with twin pregnancy were assessed with transthoracic echocardiography across the first, second, and third trimesters. Cardiac findings were compared within each group and between monochorionic (MC) and dicho-rionic (DC) pregnancies.

RESULTS

Overall, 19 MC and 48 DC uncomplicated twin pregnancies were included. In the MC group, no significant maternal haemodynamic changes were documented across gestation, with the exception of a decrease in ejection fraction. Compared to DC pregnancies, in the MC set lower cardiac output (second and third trimester, p = 0.001 and p = 0.006, respectively) and higher total vascular resistance (first trimester, p = 0.032) were observed. Regarding the diastolic function in MC twins, significantly higher values were observed for mitral E/A ratio (third trimester, p = 0.014), septal mitral E1/A1 ratio (third trimester, p = 0.030), lateral mitral E1 (second and third trimester, p = 0.014 and p = 0.029, respectively), and E1/A1 ratio (third trimester, p = 0.006).

CONCLUSIONS

Maternal cardiac adaptation in twin pregnancy seems to differ significantly according to chorionicity. In particular, in MC pregnancies the impairment of diastolic function is less pronounced, presumably due to the lower circulating volume.

The effects of metformin on maternal haemodynamics in gestational diabetes mellitus: A pilot study

BACKGROUND

Gestational diabetes mellitus (GDM) is a major clinical challenge and is likely to remain so as the incidence of GDM continues to increase.

AIM

To assess longitudinal changes in maternal haemodynamics amongst women diagnosed with GDM requiring either metformin or dietary intervention in comparison to low-risk healthy controls.

METHODOLOGY

Fifty-six pregnant women attending their first appointment at the GDM clinic and 60 low-risk healthy pregnant controls attending their routine antenatal clinics were recruited and assigned to three groups: GDM Metformin (GDM-M), GDM Diet (GDM-D) and Control. Non-invasive assessment of maternal haemodynamics, using recognised measures of arterial stiffness and central blood pressure (Arteriograph®), were undertaken under controlled conditions within four gestational windows: antenatal; AN1 (26-28 weeks), AN2 (32-34 weeks) and AN3 (37-40 weeks), and postnatal (PN) (6-8 weeks after delivery). Data were analysed using a linear mixed model incorporating gestational age and other relevant predictors, including age, blood pressure (BP), baseline bodyweight and pulse as fixed effects, and patient as a random effect.

RESULTS

Fitted linear mixed models showed evidence of a two-way interaction effect between groups (GDM-D, GDM-M and Control) and stages of gestation (AN1, AN2, AN3 and PN) for maternal haemodynamic parameters: brachial artery augmentation index (AIx) (p = 0.004), aortic AIx (p = 0.008), and central systolic BP (p = 0.001). However, differences in respect of aortic pulse wave velocity (p = 0.001) and heart rate (p < 0.001) were only significant for gestational stage. At AN2, we did not observe any evidence that the mean brachial Aix in the GDM-M was different from the control group (p = 0.158).

CONCLUSION

AIx and central systolic BP measures of arterial stiffness are adversely affected by GDM in comparison to controls during pregnancy. The possible beneficial effects of metformin therapy seen at 32 to 34 weeks of gestation require further exploration.

Longitudinal study to assess changes in arterial stiffness and cardiac output parameters among low-risk pregnant women

AIM

A single-centre, prospective longitudinal study to assess changes in maternal arterial stiffness and cardiac output parameters among low-risk healthy pregnant women.

METHODOLOGY

Thirty low-risk, healthy, pregnant women attending their routine antenatal dating ultrasound scan were recruited. Non-invasive assessment of arterial stiffness and cardiac output was undertaken at five gestational windows from 11 to 40 weeks of pregnancy. Data were analysed using a linear mixed model incorporating time and other relevant predictors as fixed effects, and patient as a random effect.

RESULTS

Gestational age had a significant effect on all arterial stiffness parameters, including brachial augmentation index (AIx) (p = .001), aortic AIx (p = .002) and aortic pulse wave velocity (p = .002). The aortic AIx (%) reduced during pregnancy: the lowest mean (standard error, SE) was 4.07 (1.01) at 28 weeks before it increased to 7.04 (SE 1.64) at 40 weeks. Similarly, non-invasive assessments of cardiac output (p < .001), stroke volume (p = .014), heart rate (p < .001) and total peripheral resistance (p < .001) demonstrated significant changes with gestational age. Mean cardiac output (l/m) increased during pregnancy reaching a peak at 28 weeks gestation 6.66 (SE 0.28), but dropped thereafter to reach 5.71 (SE 0.25) around term.

CONCLUSION

The current study provides pregnancy normograms for gestational changes in arterial stiffness and cardiac output parameters among low-risk, healthy pregnant women. Further work will be required to assess the risk of placental mediated diseases and pregnancy outcome among pregnant women with parameters outside the normal range.