Combined impact of high body mass index and in vitro fertilization on preeclampsia risk: a hospital-based cohort study

Serum estradiol to testosterone ratio as a novel predictor of severe preeclampsia in the first trimester

Preeclampsia (PE) is the most common medical complication during pregnancy and the second leading cause of maternal death worldwide. However, a better predictive model of PE remains to be explored. A total of 15 severe preeclampsia (sPE) and 75 healthy control patients were included in this study. Patient data was obtained from September 2019 to September 2021. Nuchal translucency (NT) and crown-rump length (CRL) of the fetus were acquired by ultrasound. Maternal blood samples were collected at 11⁺⁰ to 13⁺⁶  weeks of gestation. Chemiluminescent immunoassays were used to detect serum testosterone (T) and estradiol (E2) levels. Time-resolved fluorescence analysis was used to examine the levels of serum pregnancy-associated plasma protein A (PAPPA) and β-human chorionic gonadotrophin (β-HCG) protein. The sPE group exhibited increased T levels, and decreased E2 levels and E2/T ratios from 11 to 14 weeks of gestation, compared with the control group. E2 and the E2/T ratio showed positive linear correlation with CRL in pregnant women. Body-mass-index (BMI), T, and E2 were determined to be the main factors that affected the occurrence of sPE at the 12-week gestation period time point. The receiver operating characteristic (ROC) curve revealed that the AUC of the E2/T ratio was .717. The imbalanced T and E2 levels in the patients had a specific intrinsic relevance with sPE, which suggests them as novel predictors of the sPE.

Infertility, Infertility Treatment and Cardiovascular Disease: An Overview

The prevalence of maternal cardiovascular disease (CVD) has risen throughout the developed world, reflecting an increase in acquired cardiovascular risk factors, such as hypertension and diabetes, and the improved life expectancy of those living with congenital CVD due to advances in care. Because many cardiovascular risk factors or cardiovascular conditions are associated with infertility, reproductive-aged women with CVD may increasingly seek reproductive assistance. The worldwide use of assisted reproductive technologies (ART), such as in-vitro fertilization (IVF) with or without intracytoplasmic sperm injection, or intrauterine insemination following pharmacological ovulation induction have increased steadily over the last several decades. It is incumbent among providers who care for reproductive-aged women with pre-existing CVD or CVD risk factors to understand and appreciate the types of treatments offered and inherent risks related to infertility treatments, in order to guide their patients to making safe reproductive choices in line with their values and preferences. While infertility treatments increase the risk of complicated pregnancy, whether these risks are compounded among individuals with pre-existing CVD is less well known. In this review, we summarize current available evidence regarding short-term and long-term cardiovascular implications of ART among individuals with and without CVD, as well as treatment considerations for these women. Existing knowledge gaps and priority areas for further study are presented.

Assisted reproductive technology and hypertensive disorders of pregnancy: systematic review and meta-analyses

Background

Hypertensive disorders of pregnancy (HDP) is one of the most common pregnancy complications and causes of maternal morbidity and mortality. Assisted reproductive technology (ART) has been associated with adverse pregnancy outcomes, including HDP. However, the impact of multiple pregnancies, oocyte donation, as well as fresh and frozen embryo transfer needs to be further studied. We conducted a systematic review and meta-analyses to evaluate the association between ART and HDP or preeclampsia relative to spontaneous conception (SC).

Methods

We identified studies from EMBASE, MEDLINE, and Cochrane Library (up to April 8, 2020) and manually using structured search strategies. Cohort studies that included pregnancies after in vitro fertilization (IVF) with or without intracytoplasmic sperm fertilization (ICSI) relative to SC with HDP or preeclampsia as the outcome of interest were included. The control group was women who conceived spontaneously without ART or fertility medications. The pooled results were reported in odds ratios (OR) with 95% confidence intervals based on random effects models. Numbers needed to harm (NNH) were calculated based on absolute risk differences between exposure and control groups.

Results

Eighty-five studies were included after a screening of 1879 abstracts and 283 full text articles. Compared to SC, IVF/ICSI singleton pregnancies (OR 1.70; 95% CI 1.60–1.80; I² = 80%) and multiple pregnancies (OR 1.34; 95% CI 1.20–1.50; I² = 76%) were both associated with higher odds of HDP. Singleton pregnancies with oocyte donation had the highest odds of HDP out of all groups analyzed (OR 4.42; 95% CI 3.00–6.51; I² = 83%). Frozen embryo transfer resulted in higher odds of HDP (OR 1.74; 95% CI 1.58–1.92; I² = 55%) than fresh embryo transfer (OR 1.43; 95% CI 1.33–1.53; I² = 72%). The associations between IVF/ICSI pregnancies and SC were similar for preeclampsia. Most interventions had an NNH of 40 to 100, while singleton and multiple oocyte donation pregnancies had particularly low NNH for HDP (16 and 10, respectively).

Conclusions

Our meta-analysis confirmed that IVF/ICSI pregnancies are at higher odds of HDP and preeclampsia than SC, irrespective of the plurality. The odds were especially high in frozen embryo transfer and oocyte donation pregnancies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03938-8.

Association Between Pre-Pregnancy Body Mass Index and Maternal and Neonatal Outcomes of Singleton Pregnancies After Assisted Reproductive Technology

OBJECTIVE

To study the association between pre-pregnancy body mass index (BMI) and adverse maternal and neonatal outcomes of singleton pregnancies after assisted reproductive technology (ART).

METHODS

This hospital-based retrospective cohort study of women with live singleton births through ART in China from January 2015 to August 2020 included 3043 Chinese women. According to the latest BMI classification standard of Asian women, the women included in this study were classified as underweight (BMI <18.5 kg/m²), normal (BMI 18.5 to <23 kg/m²), overweight (BMI 23 to <27.5 kg/m²), and obese (BMI ≥27.5 kg/m²). We compared the risk of adverse outcomes of different pre-pregnancy BMI values of women with singleton pregnancies conceived through ART. We used Logistic regression analysis to estimate the associations between pre-pregnancy BMI and adverse perinatal and neonatal outcomes.

RESULTS

Our findings showed that women who were overweight or obese before pregnancy through ART are more likely to have a cesarean section, gestational diabetes mellitus, gestational hypertension, and preeclampsia, regardless of whether confounding factors are adjusted. Moreover, pre-pregnancy obesity was more associated with a higher risk of these adverse outcomes than pre-pregnancy overweight. In addition, neonates from women who had obesity before pregnancy through ART were more likely to have macrosomia; adjusted odds ratios and 95% confidence intervals were 3.004 (1.693-5.330).

CONCLUSIONS

Our research showed that women who had pre-pregnancy overweight or obesity with singleton pregnancies through ART were more likely to have a cesarean section, gestational diabetes mellitus, gestational hypertension, and preeclampsia. Moreover, neonates from women who had obesity before pregnancy were more likely to have macrosomia.

Higher gestational weight gain and lower serum estradiol levels are associated with increased risk of preeclampsia after in vitro fertilization

PURPOSE

To assess the association of preeclampsia with serum estradiol (E2) and progesterone (P4) levels on the day of human chorionic gonadotropin (hCG) administration during controlled ovarian hyperstimulation (COH) for in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI).

METHODS

This was a hospital-based cohort study using clinical data from the Kaohsiung Chang Gung Memorial Hospital Obstetric and Neonatal Database (KCGMHOND) from Jan 1, 2001 to December 1, 2018.

RESULTS

A total of 622 women who had live births after fresh IVF/ICSI-ET during the study period met our inclusion criteria. Twenty-eight women (4.5%) met the diagnostic criteria for preeclampsia. However, women in the preeclampsia group had a significantly higher body weight at delivery (80.5 vs. 70.0 kg, p < 0.001) and gestational weight gain (19.6 vs. 13.0 kg, p = 0.002) and had lower use of ICSI (10.7% vs. 29.9%, p = 0.021). We performed logistic regression analysis of the relationship of patient and treatment characteristics with preeclampsia. The crude ORs indicated that young female age ≤ 34, not using ICSI, E2 on hCG day < 1200 pg/mL and gestational weight gain > 20 kg were associated with preeclampsia. After adjustment for confounding, the only factors that remained significant were E2 on hCG day < 1200 pg/mL (aOR = 4.634, 95% CI = 1.061-20.222), and gestational weight gain > 20 kg (aOR: 13.601, 95% CI: 3.784, 48.880).

CONCLUSIONS

For women receiving IVF/ICSI, lower estradiol hormone levels on the day of hCG administration and higher pregnancy weight gain are related with subsequent preeclampsia.

Association between in vitro fertilization and ischemic placental disease by gestational age

OBJECTIVE

To evaluate the association between in vitro fertilization (IVF) and ischemic placental disease (IPD), stratified by gestational age.

DESIGN

We performed a secondary analysis of a retrospective cohort study of deliveries.

SETTING

Deliveries were performed over 15 years at a single tertiary hospital.

PATIENT(S)

We included all parturients who had a live born infant or an intrauterine fetal demise (IUFD).

INTERVENTION(S)

We compared pregnancies resulting from IVF cycles to non-IVF pregnancies.

MAIN OUTCOME MEASURE(S)

The primary outcomes were preterm and term IPD (preeclampsia, placental abruption, small-for-gestational age infant [SGA], or an intrauterine fetal demise [IUFD] due to placental insufficiency).

RESULT(S)

Of the 69,084 deliveries during the study period, 3,763 (5.4%) were conceived with IVF. The incidence of preterm delivery was 32.6% in IVF pregnancies and 10.8% in non-IVF pregnancies. Multiple gestations were more common in IVF pregnancies. Compared to non-IVF pregnancies, IVF pregnancies were more likely to develop both preterm and term IPD, even after adjustment for maternal age and parity. The risk of preterm IPD was 4 times higher (95% confidence interval, 3.7-4.4) in patients who underwent IVF compared with those who did not undergo IVF. Among parturients who delivered at ≥37 weeks of gestation, IVF pregnancies had 1.7 times the risk of term IPD (95% confidence interval, 1.6-1.9) compared with non-IVF pregnancies.

CONCLUSION(S)

IVF was strongly associated with preterm IPD. We found a similar, but attenuated, association between IVF and term IPD. The stronger association with preterm IPD suggests an association between IVF and placental insufficiency.

Severe maternal morbidity in women with high BMI in IVF and unassisted singleton pregnancies

STUDY QUESTION

Is there a synergistic risk of severe maternal morbidity (SMM) in overweight/obese women who conceived by IVF compared to normal-weight women without IVF?

SUMMARY ANSWER

SMM was more common in IVF pregnancies, and among overweight/obese women, but we did not detect a synergistic effect of both factors.

WHAT IS KNOWN ALREADY

While much is known about the impact of overweight and obesity on success rates after IVF, there is less data on maternal health outcomes.

STUDY DESIGN, SIZE, DURATION

This is a population-based cohort study of 114 409 singleton pregnancies with conceptions dating from 11 January 2013 until 10 January 2014 in Ontario, Canada. The data source was the Canadian Assisted Reproductive Technologies Register (CARTR Plus) linked with the Ontario birth registry (BORN Information System).

PARTICIPANTS/MATERIALS, SETTING, METHODS

We included women who delivered at ≥20 weeks gestation, and excluded those younger than 18 years or with twin pregnancies. Women were classified according to the mode of conception (IVF or unassisted) and according to pre-pregnancy BMI (high BMI (≥25 kg/m2) or low-normal BMI (<25 kg/m2)). The main outcome was SMM, a composite of serious complications using International Classification of Diseases, 10th revision (ICD-10) codes. Secondary outcomes were gestational hypertension, pre-eclampsia, gestational diabetes and cesarean delivery. Adjusted risk ratios (aRR) with 95% CI were estimated using log binomial regression, adjusted for maternal age, parity, education, income and baseline maternal comorbidity.

MAIN RESULTS AND THE ROLE OF CHANCE

Of 114 409 pregnancies, 1596 (1.4%) were IVF conceptions. Overall, 41.2% of the sample had high BMI, which was similar in IVF and non-IVF groups. We observed 674 SMM events (rate: 5.9 per 1000 deliveries). IVF was associated with an increased risk of SMM (rate 11.3/1000; aRR 1.89, 95% CI: 1.06-3.39). High BMI was modestly associated with SMM (rate 7.0/1000; aRR 1.23, 95% CI: 1.04-1.45) There was no interaction between the two factors (P = 0.22). We noted supra-additive effects of high BMI and IVF on the risk of pre-eclampsia and gestational diabetes, but not gestational hypertension or cesarean delivery.

LIMITATIONS, REASONS FOR CAUTION

We were unable to assess outcomes according to reason for treatment. Type II error (beta ~25%) may affect our results.

WIDER IMPLICATIONS OF THE FINDINGS

Our results support previous data indicating a greater risk of SMM in IVF pregnancies, and among women with high BMI. However, these factors do not interact. Overweight and obese women who seek treatment with IVF should be counseled about pregnancy risks. The decision to proceed with IVF should be based on clinical judgment after considering an individual's chance of success and risk of complications.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Research Institute of the McGill University Health Centre (grant 6291) and also supported by the Trio Fertility (formerly Lifequest) Research Fund. The authors report no competing interests.

TRIAL REGISTRATION NUMBER

Not applicable.

Levels of sex steroid hormones and their receptors in women with preeclampsia

BACKGROUND

Pregnant women have high serum concentrations of sex steroid hormones, which are major regulators of paracrine and autocrine responses for many maternal and placental functions. The main purpose of this study was to compare patients with preeclampsia and patients with uncomplicated pregnancies in terms of serum steroid hormones (estradiol [E2], progesterone [P4], dehydroepiandrosterone sulfate [DHEAS], and testosterone [T]) throughout pregnancy and the levels of cord blood and placental steroid receptors during the third trimester.

METHODS

Quantitative real-time reverse transcription PCR, western blotting, and immunohistochemistry were used to determine the levels of steroid hormones in the serum and cord blood and the placental levels of estrogen receptor-α (ERα), ERβ, androgen receptor (AR), and progesterone receptor (PR).

RESULTS

There were 45 women in the uncomplicated pregnancy group and 30 women in the preeclampsia group. Serum levels of T were greater and serum levels of E2 were reduced in the preeclampsia group, but the two groups had similar levels of P4 and DHEAS during the third trimester. Cord blood had a decreased level of DHEAS in the preeclampsia group, but the two groups had similar levels of P4, E2, and T. The two groups had similar placental mRNA levels of ERα, ERβ, AR, and PR, but the preeclampsia group had a higher level of ERβ protein and a lower level of ERα protein. Immunohistochemistry indicated that the preeclampsia group had a greater level of ERβ in the nucleus and cytoplasm of syncytiotrophoblasts and stromal cells.

CONCLUSIONS

Women with preeclampsia had lower levels of steroid hormones, estrogen, and ERα but higher levels of T and ERβ. These molecules may have roles in the pathogenesis of preeclampsia.

Risk of ischemic placental disease in fresh and frozen embryo transfer cycles

OBJECTIVES

To evaluate the association of fresh and frozen embryo transfer with the development of ischemic placental disease (IPD), hypothesizing that differences in implantation environment affect placentation and thus pregnancy outcomes.

DESIGN

We performed a secondary analysis of a retrospective cohort study of deliveries linked to IVF cycles.

SETTING

Tertiary hospital and infertility treatment center.

PATIENT(S)

We included all women who underwent an autologous IVF cycle and had a live-born infant or an intrauterine fetal demise (IUFD). We excluded women less than 18 years of age.

INTERVENTION(S)

We compared pregnancies resulting from frozen embryo transfer (frozen) cycles with those resulting from fresh embryo transfer (fresh) cycles.

MAIN OUTCOME MEASURE(S)

The primary outcome was a composite outcome of IPD or IUFD due to placental insufficiency. Ischemic placental disease included pre-eclampsia, placental abruption, and small for gestational age (SGA). We calculated risk ratios (RRs) and 95% confidence intervals (CIs).

RESULT(S)

Compared with fresh cycles, frozen cycles had a lower risk of IPD or IUFD from placental insufficiency (RR 0.75, 95% CI 0.59-0.97). Frozen cycles also conferred a lower risk of SGA than fresh cycles (RR 0.58, 95% CI 0.41-0.81). Risks of pre-eclampsia (RR 1.3, 95% CI 0.84-1.9) and abruption (RR 1.2, 95% CI 0.56-2.4) were similar.

CONCLUSION(S)

There was a lower risk of IPD among frozen cycles compared with fresh cycles. This association was largely driven by lower risk of SGA among frozen cycles.

Placental Vascular Calcification and Cardiovascular Health: It Is Time to Determine How Much of Maternal and Offspring Health Is Written in Stone

Vascular calcification is the deposition of calcium phosphate minerals in vascular tissue. Vascular calcification occurs by both active and passive processes. Extent and tissue-specific patterns of vascular calcification are predictors of cardiovascular morbidity and mortality. The placenta is a highly vascularized organ with specialized vasculature that mediates communication between two circulatory systems. At delivery the placenta often contains calcified tissue and calcification can be considered a marker of viral infection, but the mechanisms, histoanatomical specificity, and pathophysiological significance of placental calcification are poorly understood. In this review, we outline the current understanding of vascular calcification mechanisms, biomedical consequences, and therapeutic interventions in the context of histoanatomical types. We summarize available placental calcification data and clinical grading systems for placental calcification. We report on studies that have examined the association between placental calcification and acute adverse maternal and fetal outcomes. We then review the intersection between placental dysfunction and long-term cardiovascular health, including subsequent occurrence of maternal vascular calcification. Possible maternal phenotypes and trigger mechanisms that may predispose for calcification and cardiovascular disease are discussed. We go on to highlight the potential diagnostic value of placental calcification. Finally, we suggest avenues of research to evaluate placental calcification as a research model for investigating the relationship between placental dysfunction and cardiovascular health, as well as a biomarker for placental dysfunction, adverse clinical outcomes, and increased risk of subsequent maternal and offspring cardiovascular events.

Pregnancy, birth, and infant outcomes by maternal fertility status: the Massachusetts Outcomes Study of Assisted Reproductive Technology

BACKGROUND

Births to subfertile women, with and without infertility treatment, have been reported to have lower birthweights and shorter gestations, even when limited to singletons. It is unknown whether these decrements are due to parental characteristics or aspects of infertility treatment.

OBJECTIVE

The objective of the study was to evaluate the effect of maternal fertility status on the risk of pregnancy, birth, and infant complications.

STUDY DESIGN

All singleton live births of ≥22 weeks' gestation and ≥350 g birthweight to Massachusetts resident women in 2004-2010 were linked to hospital discharge and vital records. Women were categorized by their fertility status as in vitro fertilization, subfertile, or fertile. Women whose births linked to in vitro fertilization cycles from the Society for Assisted Reproductive Technology Clinic Outcomes Reporting System were classified as in vitro fertilization. Women with indicators of subfertility but not treated with in vitro fertilization were classified as subfertile. Women without indicators of subfertility or in vitro fertilization treatment were classified as fertile. Risks of 15 adverse outcomes (gestational diabetes, pregnancy hypertension, antenatal bleeding, placental complications [placenta abruptio and placenta previa], prenatal hospitalizations, primary cesarean delivery, very low birthweight [<1500 g], low birthweight [<2500 g], small-for-gestation birthweight [z-score ≤-1.28], large-for-gestation birthweight [z-score ≥1.28], very preterm [<32 weeks], preterm [<37 weeks], birth defects, neonatal death [0-27 days], and infant death [0-364 days of life]) were modeled by fertility status with the fertile group as reference and the subfertile group as reference, using multivariate log binomial regression and reported as adjusted risk ratios and 95% confidence intervals.

RESULTS

The study population included 459,623 women (441,420 fertile, 8054 subfertile, and 10,149 in vitro fertilization). Women in the subfertile and in vitro fertilization groups were older than their fertile counterparts. Risks for 6 of 6 pregnancy outcomes and 6 of 9 infant outcomes were increased for the subfertile group, and 5 of 6 pregnancy outcomes and 7 of 9 infant outcomes were increased for the in vitro fertilization group. For 4 of the 6 pregnancy outcomes (uterine bleeding, placental complications, prenatal hospitalizations, and primary cesarean) and 2 of the infant outcomes (low birthweight and preterm) the risk was greater in the in vitro fertilization group, with nonoverlapping confidence intervals to the subfertile group, indicating a substantially higher risk among in vitro fertilization-treated women. The highest risks for the in vitro fertilization women were uterine bleeding (adjusted risk ratio, 3.80; 95% confidence interval, 3.31-4.36) and placental complications (adjusted risk ratio, 2.81; 95% confidence interval, 2.57-3.08), and for in vitro fertilization infants, very preterm birth (adjusted risk ratio, 2.13; 95% confidence interval, 1.80-2.52), and very low birthweight (adjusted risk ratio, 2.15; 95% confidence interval, 1.80-2.56). With subfertile women as reference, risks for the in vitro fertilization group were significantly increased for uterine bleeding, placental complications, prenatal hospitalizations, primary cesarean delivery, low and very low birthweight, and preterm and very preterm birth.

CONCLUSION

These analyses indicate that, compared with fertile women, subfertile and in vitro fertilization-treated women tend to be older, have more preexisting chronic conditions, and are at higher risk for adverse pregnancy outcomes, particularly uterine bleeding and placental complications. The greater risk in in vitro fertilization-treated women may reflect more severe infertility, more extensive underlying pathology, or other unfavorable factors not measured in this study.

What are the metabolic precursors which increase the risk of pre-eclampsia and how could these be investigated further

Several maternal and pregnancy characteristics have been associated with an increased risk of preeclampsia in epidemiological studies. This review discusses metabolic risk factors in particular and their interaction with other maternal and/or pregnancy characteristics. Examples of research studies that have used data from women with specific characteristics or explored the interaction between risk factors are discussed. Suggestions for future research using large data sets and incorporating knowledge of cardiovascular disease and other metabolic diseases are also highlighted.

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Obesity and nulliparity account for the largest population risk of preeclampsia.

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Low PlGF in early pregnancy is more strongly associated with preeclampsia in obese women.

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There are interactions between obesity and other characteristics which amplify the risk of preeclampsia e.g. ART, ethnicity.

Clinical risk factors for pre-eclampsia determined in early pregnancy: systematic review and meta-analysis of large cohort studies

OBJECTIVE

To develop a practical evidence based list of clinical risk factors that can be assessed by a clinician at ≤ 16 weeks' gestation to estimate a woman's risk of pre-eclampsia.

DESIGN

Systematic review and meta-analysis of cohort studies.

DATA SOURCES

PubMed and Embase databases, 2000-15.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Cohort studies with ≥ 1000 participants that evaluated the risk of pre-eclampsia in relation to a common and generally accepted clinical risk factor assessed at ≤ 16 weeks' gestation.

DATA EXTRACTION

Two independent reviewers extracted data from included studies. A pooled event rate and pooled relative risk for pre-eclampsia were calculated for each of 14 risk factors.

RESULTS

There were 25,356,688 pregnancies among 92 studies. The pooled relative risk for each risk factor significantly exceeded 1.0, except for prior intrauterine growth restriction. Women with antiphospholipid antibody syndrome had the highest pooled rate of pre-eclampsia (17.3%, 95% confidence interval 6.8% to 31.4%). Those with prior pre-eclampsia had the greatest pooled relative risk (8.4, 7.1 to 9.9). Chronic hypertension ranked second, both in terms of its pooled rate (16.0%, 12.6% to 19.7%) and pooled relative risk (5.1, 4.0 to 6.5) of pre-eclampsia. Pregestational diabetes (pooled rate 11.0%, 8.4% to 13.8%; pooled relative risk 3.7, 3.1 to 4.3), prepregnancy body mass index (BMI) >30 (7.1%, 6.1% to 8.2%; 2.8, 2.6 to 3.1), and use of assisted reproductive technology (6.2%, 4.7% to 7.9%; 1.8, 1.6 to 2.1) were other prominent risk factors.

CONCLUSIONS

There are several practical clinical risk factors that, either alone or in combination, might identify women in early pregnancy who are at "high risk" of pre-eclampsia. These data can inform the generation of a clinical prediction model for pre-eclampsia and the use of aspirin prophylaxis in pregnancy.

A Focus on Maternal Health Before Assisted Reproduction: Results From a Pilot Survey of Canadian IVF Medical Directors

OBJECTIVE

To describe current physician practice patterns in Canada with regard to performing in vitro fertilization in high-risk patients.

METHODS

All medical directors of IVF clinics registered with the Canadian Fertility and Andrology Society (n=35) were invited to participate in an online survey between January and May 2014. We carried out descriptive analyses of participants' responses regarding implementation of local restrictive policies for access to IVF. Whether practice patterns differed in hospital versus community-based clinics was assessed using chi-square testing with significance set at alpha<0.05.

RESULTS

The response rate was 77.1%. More than one half of clinics (55.6%) were university-affiliated, and 29.6% were hospital-based. The majority of respondents (70.4%) used an upper age limit for permitting IVF (median 50 years, IQR 44 to 50), mostly because of lower pregnancy and live birth rates. Approximately one half of respondents limited treatment according to BMI (median upper permitted BMI 38 kg/m2, IQR 35 to 40 kg/m2) to minimize complications during pregnancy. Most respondents (77.8%) believed that routine pre-IVF medical assessment would be useful in their daily practice. There was a non-significant trend towards more restrictive policies in hospital-based clinics compared with community-based clinics.

CONCLUSION

Our findings confirm that Canadian reproductive medicine physicians are taking maternal health factors into consideration when assessing patients' suitability for IVF. Nevertheless, there is between-clinic variability in the parameters used to assess eligibility for treatment. In light of the changing maternal demographic, more research is needed on assisted reproductive technology and perinatal outcomes in women who are at risk for pregnancy complications.