The predictive factors for early spontaneous miscarriage in IVF/ICSI cycles

There are potential independent factors for the prediction of early spontaneous miscarriage and clinical pregnancy after IVF/ICSI treatment.

Key Points

Highlights:

• Female age, number of previous miscarriages and endometrial thickness on the day of embryo transfer are the main predictive factors for the determination of early spontaneous miscarriage rate in IVF/ICSI-conceived clinical pregnancies.  

 Importance:

• The women undergoing IVF/ICSI treatment and healthcare personnel should have knowledge about the predictive factors which determine early spontaneous pregnancy loss and pregnancy rates.

 What’s done here? 

• This retrospective study was conducted to clarify the importance of predictive factors for the success of IVF/ICSI treatment by examining the infertile women who underwent assisted reproductive technology (ART) between January 2010 and December 2016 were included, from the First Affiliated Hospital of Zhengzhou University.
•  on a total of 21,485 clinical pregnancy cycles, with an early spontaneous miscarriage rate of 12.58%.
• Women from endometriosis and the control group were compared based on female age, body mass index (BMI), number of previous miscarriages, infertility diagnosis and type and cycle characteristics for the prediction of early spontaneous miscarriage rate. 

Key results: 

• Older women, and those with higher BMI, secondary infertility type, having more than 3 previous miscarriages, poor ovarian reserve, frozen-thawed cycles, modified super long ovarian stimulation protocol, having less than 5 oocytes retrieved and endometrial thickness less than 8 mm were at higher risk for early spontaneous miscarriage. Freeze-thaw protocol or number of embryos transferred had no significant effect on this rate.
• In comparison to women having male factor infertility alone, the early spontaneous miscarriage rate was significantly higher in the patients younger than 35 years and having PCOS and uterine malformations. Endometriosis did not make any significant difference for early spontaneous miscarriage rates in this age group.
• However, PCOS, uterine malformations and endometriosis had no significant effect on early spontaneous miscarriage rates in women older than 35 years old.
• Female age and number of previous miscarriages were determined as risk factors, while endometrial thickness on the day of embryo transfer was determined as a protective factor for early spontaneous miscarriage based on logistic regression analysis.
• Frozen embryo transfer was a risk factor for early spontaneous miscarriage in women younger than 35 years, whereas it was detected as a protective factor in women older than 35 years.

Strengths and Limitations 

• This is the first study investigating the predictive factors for early spontaneous miscarriage in a large sample size from a single center.
• The retrospective design can be accepted as a limitation.
• Detailed information of the patients such as the stage of endometriosis, the status of PCOS, comorbidities has not been reported.

Lay Summary

The most common presenting complaints of endometriosis are mainly dysmenorrhea, dyspareunia, chronic pelvic pain, and infertility. Affected women demand therapy for these symptoms of endometriosis, notably fertility problems.

The clinical pregnancy rate has increased up to 60% in assisted reproductive technology (ART) clinics due to the developments of in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) techniques. However, unfortunate obstetric outcomes such as biochemical pregnancy, ectopic pregnancy, spontaneous miscarriage, and stillbirth may be experienced resulting in decreased live birth rates as in spontaneous pregnancies.

Furthermore, these women seeking IVF/ICSI treatments have a higher risk for these poor obstetric outcomes due to advanced maternal age, poor ovarian reserve, and oocyte chromosomal abnormalities.

Early spontaneous miscarriage is defined as miscarriages occurring before 14 gestational weeks. Bu et al, a group of scientists from China, published a study entitled “Factors related to early spontaneous miscarriage during IVF/ICSI treatment: an analysis of 21,485 clinical pregnancies” in the journal named Reproductive BioMedicine Online. These authors aimed to define the potential early spontaneous miscarriage risk factors in women having clinical pregnancies after IVF/ICSI treatments.

They investigated 21,485 clinical pregnancy cycles, women were compared based on female age, body mass index (BMI), the number of previous miscarriages, infertility diagnosis, the type and cycle characteristics for the prediction of early spontaneous miscarriage rate in patients with polycystic ovary syndrome (PCOS), uterus malformation and endometriosis comparing with the patients having only male factor infertility.

Female age, BMI, infertility type (primary or secondary), number of previous miscarriages, infertility diagnosis, cycle type (fresh or frozen-thawed), ovarian stimulation protocol, number of oocytes retrieved and endometrial thickness were identified as the predictive factors for early spontaneous miscarriage rate. In women younger than 35 years old, PCOS and uterine malformations were clarified as the risk factors for early spontaneous miscarriage, while endometriosis did not make any significant difference for early spontaneous miscarriage rate.

However, PCOS, uterine malformations and endometriosis had no significant effect on early spontaneous miscarriage in women older than 35 years old. Female age, number of previous miscarriages and endometrial thickness on the day of embryo transfer were accepted as potential independent factors for early spontaneous miscarriage in IVF/ICSI-conceived clinical pregnancies.

“Frozen embryo transfer increased the spontaneous miscarriage rate in patients <35 years old but decreased the spontaneous miscarriage rate in patients ≥35 years old compared with fresh cycles.” the authors added.

Research Source: https://www.ncbi.nlm.nih.gov/pubmed/31883882