Assisted Reproductive Techniques in a Patient with History of Venous Thromboembolism: A Case Report and Review of Literature

We report a patient with a history of venous thrombosis following oral contraceptive pills who was planned for in vitro fertilization (IVF)-intracytoplasmic sperm injection for male factor infertility. This article discusses the mechanisms for predisposition to thrombosis during assisted reproduction in patients at high risk. Assessment of risk before commencement of treatment, use of mild stimulation, antagonist protocol, avoiding ovarian hyperstimulation, use of gonadotropin-releasing hormone agonist trigger and avoiding exposure to human chorionic gonadotropin, frozen embryo transfer in a natural cycle, single embryo transfer, avoiding multiple pregnancy, and use of prophylactic or therapeutic anticoagulation are the various risk-reduction strategies that must be adopted during IVF treatment to reduce the risk of thrombosis to that of natural conception.

Pregnancy Outcomes of In Vitro Fertilization with or without Ovarian Hyperstimulation Syndrome: A Retrospective Cohort Study in Chinese Patients

Background:

The effect of ovarian hyperstimulation syndrome (OHSS) on pregnancy outcomes of in vitro fertilization (IVF) patients is still ambiguous. This study aimed to analyze pregnancy outcomes of IVF with or without OHSS in Chinese patients.

Methods:

A retrospective cohort study was undertaken to compare pregnancy outcomes between 190 women with OHSS and 197 women without OHSS. We examined the rates of clinical pregnancy, multiple pregnancies, miscarriage, live birth, preterm delivery, preterm birth before 34 weeks’ gestation, cesarean delivery, low birth weight (LBW), and small-for-gestational age (SGA) between the two groups. Odds ratios (ORs) and 95% confidence intervals (CIs) of measure of clinical pregnancy were also analyzed.

Results:

The clinical pregnancy rate of OHSS patients was significantly higher than that of non-OHSS patients (91.8% vs. 43.5%, P < 0.001). After controlling for drug protocol and causes of infertility, the adjusted ORs of moderate OHSS and severe/critical OHSS for clinical pregnancy were 4.65 (95% CI, 1.86–11.61) and 5.83 (95% CI, 3.45–9.86), respectively. There were no significant differences in rates of multiple pregnancy (4.0% vs. 3.7%) and miscarriage (16.1% vs. 17.5%) between the two groups. With regard to ongoing clinical pregnancy, we also found no significant differences in the rates of live birth (82.1% vs. 78.8%), preterm delivery (20.9% vs. 17.5%), preterm birth before 34 weeks’ gestation (8.6% vs. 7.9%), cesarean delivery (84.9% vs. 66.3%), LBW (30.2% vs. 23.5%), and SGA (21.9% vs. 17.6%) between the two groups.

Conclusion:

OHSS, which occurs in the luteal phase or early pregnancy in IVF patients and represents abnormal transient hemodynamics, does not exert any obviously adverse effect on the subsequent pregnancy.

Thrombosis following ovarian hyperstimulation syndrome

The aim of this review is to analyse the pathophysiology and complications of thrombosis in conjuction with ovarian hyperstimulation syndrome (OHSS) following ovulation induction and to suggest practical guidelines usefull for the prevention and treatment. Although the incidence of thrombosis varies from 0.2% among in vitro fertilization (IVF) cycles and up to 10% for severe cases of the syndrome, it represents the most dangerous complication of OHSS. Different changes in haemostatic markers have been found to create a state of hypercoagulability, but no single standard test is available to estimate the state of thrombosis. The role of markers for thrombophilia is controversial. Thromboses are mostly venous (67-75%) involving upper limbs and neck, then arterial (25-33%) which are mainly intracerebral. The predominant sites of venous thromboembolism in the upper part of the body may be explained by higher concentrations of estrogens drained through lymphatic ducts from ascites and by compression of rudimentary branchyal cysts. Once early diagnosis is established, it is crucial to use an anticoagulant treatment with heparin proceeded with thromboprophylaxis. However, identification of patients at risk and preventive measures of OHSS are the best means in reducing the risk of thrombosis after ovarian stimulation.

Risk of thrombosis in women with malignancies undergoing ovarian stimulation for fertility preservation

BACKGROUND

Compared with the general population, cancer patients have a higher risk of venous thromboembolism as well as arterial thrombotic events such as stroke, myocardial infarction and peripheral arterial embolism. Therefore a possible concern for women with malignancies undergoing ovarian stimulation for fertility preservation is the increased risk of venous or arterial thrombosis.

METHODS

In this article, we revised current available literature on the risk of thrombosis in patients with cancer and in women undergoing ovarian stimulation, with the ultimate aim of drawing some indications for preventive measures.

RESULTS

Unfortunately, there are no specific data on the risk of thrombosis in women with cancer undergoing ovarian stimulation for fertility preservation. However, the literature suggests that the cancer type and stage, surgery, and chemotherapy all influence the risk of venous and, possibly, arterial thrombosis. Reports of cases of ovarian stimulation in women without malignancies have shown that venous thrombosis rarely occurs unless a pregnancy is achieved, while arterial thrombosis can occur in the absence of pregnancy but is usually only associated with ovarian hyperstimulation syndrome (OHSS). OHSS increases the risk of thrombotic events, but only the early form of the syndrome is relevant for women undergoing fertility preservation.

CONCLUSIONS

The available evidence on the risks of thrombosis for women undergoing ovarian stimulation for fertility preservation due to a malignancy is reassuring. However the avoidance of the early form of OHSS in women preserving oocytes/embryos due to malignancy is crucial. For these cycles, we advocate the use of a regimen of ovarian stimulation with gonadotrophin releasing hormone (GnRH) antagonists using GnRH agonists to trigger ovulation, an approach that has been shown to markedly reduce the risk of OHSS. Antithrombotic prophylaxis should be administered only to selected subgroups of women such as those with other risk factors or those who do develop early OHSS.