Perimenopausal pregnancy rate

Fertility around the perimenopause is reduced.

Pregnancy rate in those not using contraception is:

• 10-20 per 100 women years at 45
• 5 per 100 women years at 50

Women should be informed that although a natural decline in fertility occurs with age and spontaneous pregnancy is rare after age 50, effective contraception is required until menopause to prevent an unintended pregnancy.

• fertility naturally decreases as age increases, with women experiencing a relatively steep decline from the mid-30s onwards mainly due to diminishing quality and quantity of oocytes
  
  
• the chance of pregnancy for a woman having unprotected sexual intercourse (UPSI) over the course of a year is around 10-20% for women aged 40-44 and closer to 12% for women 45-49. Spontaneous pregnancy is rare in women over 50
  
  
• women over 40 who are sexually active should use contraception if they do not wish to become pregnant

Reference:

1. FSRH (September 2019). Contraception for Women Aged Over 40 Years.