Know More About Chemical/Biochemical Pregnancy – The Most Common Type Of Miscarriage

So, you missed your period and took a test and saw a faint line and found out your pregnant. Just to be 100% sure you take another test after a week or two after, or you suddenly get your period and you freak out and take another pregnancy test and it comes negative! In both cases, there could have been what is known as a “chemical pregnancy”.

What exactly is a chemical/biochemical pregnancy?

A chemical pregnancy, or a biochemical pregnancy, is a very early miscarriage (as early as week 4 post-conception). The reason it is referred to as a “chemical pregnancy” is that it is diagnosed only biochemical means.

The fertilized egg (after the sperm fuses with the egg) fails to implant in the uterus and still produces the pregnancy hormone hCG (human chorionic gonadotropin) in sufficient quantities to give a positive pregnancy test. In reality, there is no pregnancy at all as the natural progression of the fertilized egg to an embryo and fetus fails to occur due to lack of implantation. So, it is not fertile enough to grow through the full cycle of conception.

So, is chemical pregnancy diagnosed easily?

It is quite difficult to know if you have had a chemical pregnancy, as it is an early miscarriage. It should also be known that about week 5 of gestation the yolk sac is noticeable in an ultrasound. So, if you miscarry before 5 weeks, it is difficult to detect it under routine investigations.

Also as before 5 weeks, many women don’t even have an idea that they had a chemical pregnancy, or just assume it was a delayed menstrual cycle/period.

How common is the occurrence of a chemical pregnancy?

Scientific studies show that anywhere from 10 to 25% of the clinically recognized pregnancies mostly end in a miscarriage. And amongst early miscarriages, chemical pregnancies account to a staggering 50 to 75 % of all miscarriages.

What are the causes of a chemical pregnancy?

The main reasons for an early miscarriage include:

  • Chromosomal instability: There is an imbalance of either the 23 pairs of chromosomes from the mother, father or both.
  • Hormonal imbalance: In the mother, if there is a low level of progesterone.
  • Uterine problems: If the pregnant woman has a medical condition which physically impairs the growth of a healthy fetus like uterine fibroids, a scar from a previous surgical abortion etc.
  • Medical conditions: Any autoimmune disorders, chronic illness (like diabetes).
  • High fever: that leads to generalized weakness
  • Advanced maternal age: If the expectant mother’s age is more than 35 years.
  • Miscellaneous causes:
    • trauma, accident
    • excessive drinking &/or smoking
    • recent infections
    • drug usage

So, what happens in a chemical pregnancy?

Chemical pregnancy, at times, goes completely unnoticed as bleeding. It usually is delayed by a few days or comes round about the same time as a normally expected period. The only difference between the two is that:

  • the bleeding would be heavier/longer by a few days
  • the cramping would be more

Is it okay to plan for a child immediately after a chemical pregnancy?

Well, there is no hard and fast rule that you cannot start trying for another baby immediately. It would most likely be safe for you to speak to your doctor and then make an informed decision.

But, in most instances, you may not even know that you have had a chemical pregnancy or an early abortion. So, planning may not be even required.




Dr. Aishwarya Rajeev has completed her MDS degree and is currently pursuing her PhD. She is an avid reader and loves to teach and write!

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