Corpus luteum number and the maternal renin-angiotensin-aldosterone system as determinants of utero-placental (vascular) development: the Rotterdam Periconceptional Cohort.

BACKGROUND: Pregnancies with > 1 corpus luteum (CL) display a hyperdynamic circulation and an increased risk of small-for-gestational age deliveries. Among the factors released by the CL is prorenin, the inactive precursor of renin. Since the renin-angiotensin-aldosterone system (RAAS) is involved in early hemodynamic pregnancy adaptation, we linked both CL number and first-trimester concentrations of prorenin (as an indicator of RAAS activity) and the aldosterone/renin ratio (as an indicator of angiotensin-independent aldosterone effectiveness) to non-invasive markers of utero-placental (vascular) development, measured longitudinally from the first trimester onwards. METHODS: A total of 201 women, who conceived naturally or after in-vitro fertilization treatment (with 0 (n = 8), 1 (n = 143), or > 1 (n = 51) CL), were selected from the Rotterdam Periconceptional Cohort. Maternal RAAS components were determined at 11 weeks gestation. Placental volume and utero-placental vascular volume were measured from transvaginal 3D ultrasound scans at 7, 9 and 11 weeks gestation, pulsatility and resistance indices of the uterine arteries were assessed by pulsed wave Doppler ultrasounds at 7, 9, 11, 13, 22 and 32 weeks gestation. At birth placental weight was obtained using standardized procedures. RESULTS: Pregnancies without a CL show lower uterine artery indices throughout gestation than 1 CL and > 1 CL pregnancies, while parameters of placental development are comparable among the CL groups. After adjustment for patient- and treatment-related factors, first-trimester prorenin concentrations are positively associated with uterine artery pulsatility and resistance indices (ß 0.06, 95% CI 0.01;0.12, p = 0.04 and ß 0.10, 95% CI 0.01;0.20, p = 0.04, respectively), while high prorenin concentrations are negatively associated with first-trimester utero-placental vascular volume (ß -0.23, 95% CI -0.44;-0.02, p = 0.04) and placental weight (ß -93.8, 95%CI -160.3;-27.4, p = 0.006). In contrast, the aldosterone/renin ratio is positively associated with first-trimester placental volume (ß 0.12, 95% CI 0.01;0.24, p = 0.04). CONCLUSIONS: The absence of a CL, resulting in low prorenin concentrations, associates with low uterine artery pulsatility and resistance, while high prorenin concentrations associate with a low utero-placental vascular volume and weight. These data support a scenario in which excess prorenin, by upregulating angiotensin II, increases uterine resistance, thereby preventing normal placental (vascular) development, and increasing the risk of small-for-gestational age deliveries. Simultaneously, high aldosterone concentrations, by ensuring volume expansion, exert the opposite.

Periconceptional maternal and paternal homocysteine levels and early utero-placental (vascular) growth trajectories: The Rotterdam periconception cohort.

INTRODUCTION: Maternal elevated plasma total homocysteine (tHcy) is involved in the origin of several placenta-related pregnancy complications. The first trimester is the most sensitive period for placentation influenced by maternal and paternal health. The aim is to study associations between periconceptional parental tHcy levels and utero-placental growth trajectories in the first trimester of pregnancy. METHODS: Pregnant women and their partners were enrolled before 10 weeks of gestation in the Virtual Placenta study as subcohort of the Rotterdam periconception cohort (Predict study). A total of 190 women with a singleton pregnancy, of which 109 conceived naturally and 81 after IVF/ICSI treatment, were included. We measured serial utero-placental vascular volumes (uPVV) and placental volumes (PV) at 7, 9 and 11 weeks of gestation. First-trimester trajectories of PV were also measured in 662 pregnancies from the total Predict study. RESULTS: Comparing all participants of the virtual placenta study, no association between maternal tHcy and uPVV was observed. However, in IVF/ICSI pregnancies sub-analyses showed significantly negative associations between maternal tHcy in the 3rd and 4th quartile and uPVV trajectories (beta: -0.38 (95%CI -0.74 to -0.02) and beta: -0.42 (95% CI -0.78 to -0.05), respectively) with the 1st quartile as reference. Analysis in the total Predict cohort showed similar negative associations for the total study population. DISCUSSION: Periconceptional high maternal tHcy levels are associated with smaller placental growth trajectories depicted as PV and uPVV in the first trimester of pregnancy. The stronger negative associations with uPVV in IVF/ICSI pregnancies underline the need for further investigation.

The influence of frozen-thawed and fresh embryo transfer on utero-placental (vascular) development: the Rotterdam Periconception cohort.

STUDY QUESTION: Does frozen-thawed or fresh embryo transfer (ET) influence utero-placental (vascular) development, when studied using three-dimensional (3D) ultrasound and virtual reality imaging techniques? SUMMARY ANSWER: In the first trimester, placental developmental parameters, that is, placental volume (PV) and utero-placental vascular volume (uPVV), were comparable between pregnancies resulting from frozen-thawed ET, fresh ET and natural conception; and in the second and the third trimester, uterine artery Doppler indices were lower in pregnancies after frozen-thawed ET compared to pregnancies after fresh ET and natural conception. WHAT IS KNOWN ALREADY: Pregnancies after frozen-thawed ET are at risk of developing placenta-related pregnancy complications. There is strong evidence that impaired first-trimester spiral artery remodelling is involved in the pathophysiology of these complications. Studies on longitudinal placental development in pregnancies with different modes of conception, that is, after frozen-thawed ET, fresh ET or natural conception, are lacking. STUDY, DESIGN, SIZE, DURATION: Women with singleton pregnancies were included before 10 weeks of gestation, between January 2017 and July 2018, as a subcohort of the ongoing Rotterdam Periconception cohort. Results were partially validated in 722 women from the total cohort, which was conducted from November 2010 onwards. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 214 women, of whom 32 conceived after frozen-thawed ET, 56 conceived after fresh ET and 126 conceived naturally, were selected. PV and uPVV measurements were obtained at 7, 9 and 11 weeks of gestation by transvaginal 3D (power Doppler) ultrasound. The uterine artery pulsatility index (UtA-PI) and resistance index (UtA-RI) were measured transvaginally at 7, 9, 11 and 13 weeks and abdominally at 22 and 32 weeks of gestation by pulsed wave Doppler ultrasound. In the validation cohort, the PV was measured in 722 women. Associations between mode of conception and placental development were studied using linear mixed models. MAIN RESULTS AND THE ROLE OF CHANCE: First-trimester parameters of placental development, that is, PV, uPVV, UtA-PI and UtA-RI, were comparable between pregnancies after frozen-thawed and fresh ET and naturally conceived pregnancies. In our validation cohort, comparable results were found for PV. However, the second- and third-trimester UtA-PI and UtA-RI in pregnancies after frozen-thawed ET were significantly lower than in pregnancies after fresh ET (ßUtA-PI -0.158 (95% CI: -0.268, -0.048), P = 0.005; ßUtA-RI -0.052 (95% CI: -0.089, -0.015), P = 0.006). The second- and third-trimester uterine artery indices in pregnancies after fresh ET were comparable to those in pregnancies after natural conception. LIMITATIONS, REASONS FOR CAUTION: The main limitation of this study is the lack of power to optimally detect differences in placental development and placenta-related pregnancy outcomes between pregnancies after different modes of conception. Moreover, our population was selected from a tertiary hospital and included a relatively limited number of pregnancies. Therefore, external validity of the results should be confirmed in a larger sample size. WIDER IMPLICATIONS OF THE FINDINGS: These findings indicate no significant impact of conception mode on early placental development and a beneficial impact for frozen-thawed ET on the second- and third-trimester Doppler indices. This suggests that frozen-thawed ET may not be as detrimental for placental perfusion as previous research has demonstrated. As the number of clinics applying the 'freeze-all strategy' increases, future research should focus on establishing the optimal uterine environment, with regards to hormonal preparation, prior to ET to reduce placental-related pregnancy complications after frozen-thawed ET. STUDY FUNDING/COMPETING INTEREST(S): This research was funded by the Erasmus MC Medical Research Advisor Committee's 'Health Care Efficiency Research' program and the department of Obstetrics and Gynaecology of the Erasmus MC, University Medical Center, Rotterdam, The Netherlands. JSEL reports grants and personal fees from Ferring, personal fees from Titus Healthcare, grants and personal fees from Ansh Labs, grants from NIH, grants from Dutch Heart Association and grants from ZonMW outside the submitted work. None of the other authors have a conflict of interest. TRIAL REGISTRATION NUMBER: Registered at the Dutch Trial Register (NTR6684).

Larger First-Trimester Placental Volumetric Parameters Are Associated With Lower Pressure and More Flow-Mediated Vasodilation of the Fetoplacental Vasculature After Delivery.

OBJECTIVE: To explore the correlation between in vivo placental volumetric parameters in the first trimester of pregnancy and ex vivo parameters of fetoplacental vascular function after delivery. METHODS: In ten singleton physiological pregnancies, placental volume (PV) and uteroplacental vascular volume (uPVV) were measured offline in three-dimensional ultrasound volumes at 7, 9, and 11 weeks gestational age (GA) using Virtual Organ Analysis and Virtual Reality. Directly postpartum, term placentas were ex vivo dually perfused and pressure in the fetoplacental vasculature was measured to calculate baseline pressure (pressure after a washout period), pressure increase (pressure after a stepwise fetal flow rate increase of 1 mL/min up to 6 mL/min) and flow-mediated vasodilation (FMVD; reduction in inflow hydrostatic pressure on the fetal side at 6 mL/min flow rate). Correlations between in vivo and ex vivo parameters were assessed by Spearman's correlation coefficients (R). RESULTS: Throughout the first trimester, PV was negatively correlated with pressure increase (R growth = -0.84) and, at 11 weeks GA, also positively correlated with FMVD (R = 0.89). At 7 weeks GA, uPVV and uPVV/PV ratio were negatively correlated with pressure increase (R = -0.58 and R = -0.81, respectively) and positively correlated with FMVD (R = 0.62 and R = 0.90, respectively). DISCUSSION: Mainly in the early first trimester, larger placental volumetric parameters are associated with lower pressure and more FMVD in the fetoplacental vasculature after delivery. This may suggest that larger and/or more vascularized placentas in early pregnancy have better adaptive mechanisms and possibly lead to better pregnancy outcomes.

The value of Anti-Müllerian hormone in low and extremely low ovarian reserve in relation to live birth after in vitro fertilization.

OBJECTIVE: To determine the relation of Anti-Müllerian hormone (AMH) with live birth after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in women with (extremely) low ovarian reserve. STUDY DESIGN: This study was a retrospective cohort study in a Dutch tertiary fertility clinic. Between January 2009 and March 2012, AMH levels were measured in infertile women when ≥36 years of age or when showing clinical signs of diminished ovarian reserve, before they underwent IVF or ICSI treatment. Ultimately, 156 women with (extremely) low ovarian reserve were included and evaluated for cumulative live birth rates. Of each woman, only one treatment cycle was analyzed, either the one in which she became pregnant or her first treatment cycle if she did not reach pregnancy. The relation between AMH and live birth was evaluated with multivariable logistic regression analysis. A ROC curve was composed to evaluate the discriminative value of AMH in relation to live birth after IVF/ICSI. RESULTS: Thirty-three out of 156 women (21.2%) gave live birth. Live birth was significantly lower in women with AMH ≤0.1ng/ml (4/37 women; 10.8%) or AMH >0.1-0.4ng/ml (7/42 women; 16.7%), compared to women with AMH >0.4-1.05ng/ml (22/77 women; 28.6%), p<0.001. Multivariable logistic regression revealed an association between the severity of low ovarian reserve and live birth (per 0.1ng/ml increase in AMH value, Odds ratio 1.21; 95% CI 1.07-1.36). CONCLUSIONS: The level of AMH is related to live birth after IVF/ICSI in women with (extremely) low ovarian reserve. The live birth rate in women with AMH >0.4ng/ml was significantly higher than in women with AMH ≤0.4ng/ml. AMH could serve as a tool in the pre-treatment counseling for pregnancy and live birth chances in women with (extremely) low ovarian reserve.