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A very early miscarriage: Chemical pregnancy

Her eyes were red and tears were rolling down her cheeks when I told her that her blood level of B-HCG, (pregnancy hormone), was declining. A week ago, she was elated and thrilled when she discovered that she was pregnant after she underwent intra-uterine insemination of sperm (IUI) for the first time.

N, 39, a housewife was married for 5 years and had been trying actively to conceive since marriage. She had failed IVF 3 times in the past 2 years. It was a roller coaster ride and she was emotionally spent and went into a period of depression. Encouraged by her spouse, she came for a consultation to find out more about IUI.

Physical and ultrasound examination revealed that her reproductive system was normal. Semen analysis of her spouse was also normal. The couple was suffering from unexplained infertility, a condition in which no identifiable cause can be found with normal fertility tests.

Superovulation and IUI were discussed and N was counselled on the risks and success rate of the procedure. (Please refer to SO-IUI on the website). Her blood level of B-HCG was 450 IU/L sixteen days after IUI. This was increased to 920IU/L two days later. On her next review after a week, the level dropped to 864 IU/L which was further reduced to 439 IU/L the next day. Vaginal ultrasound examination did not reveal any gestational sac. N was having a very early miscarriage, otherwise known as a chemical pregnancy.

What is a chemical pregnancy?

A chemical pregnancy is a very early miscarriage. The fertilised egg is able to produce enough B-HCG to cause a positive pregnancy test but fails to implant completely into the womb. This usually takes place around 5 weeks of gestation and the pregnancy sac cannot be seen by ultrasound examination.

How common is a chemical pregnancy?

Chemical pregnancy is fairly common. The reported incidence varies between 8% to 75 % of all conceptions. The wide variation is due to the fact that the exact number of chemical pregnancies is difficult to estimate because many of these pregnancies end without any symptoms. Most women who have a chemical pregnancy would never know that they had been pregnant and treat it as “delayed periods”.

What could be the symptoms of chemical pregnancy if any?

  • Delayed period

  • Spotting a few days before period is due

  • More menstrual cramps than usual

  • Heavier menses with clots than usual

What are the causes of a chemical pregnancy?