In Vitro Fertilization: What is the 2ww (2-Week-Wait)?

In vitro fertilization (IVF) is a method of conceiving a baby that involves combining the sperm and egg outside the body in a laboratory dish. There are several stages to the procedure, the last of which is the transfer of the embryo into the mother’s uterus. But it's also the starting point of a new phase: The dreaded two-week wait before you can take a pregnancy test. This period is important because it's when implantation of the embryo takes place. It's also when the earliest signs of pregnancy may start to appear.

The two-week wait period

The two-week waiting period, also known as the 2WW, can be among the most emotional stages after IVF. That's because during this time, the embryo may or may not attain implantation in the uterus. If the implantation successfully takes place, you become pregnant. If the implantation is not successful, the entire IVF procedure will have to be repeated.

The main factors that influence whether the embryo is successfully implanted or not include:

  • The parents' ages,
  • The parents' genes, and
  • Your overall state of health.

There is no scientific evidence to suggest that your level of physical activity has any effect on implantation, though of course you should discuss any exercise plans with your doctor.

Pregnancy tests during the 2WW

This two-week waiting period happens during the second half of your cycle, called the luteal phase, after ovulation has taken place. If the procedure was a success, there will already be all sorts of changes happening in your body during this time, though you may not notice them. The more noticeable symptoms can include mild queasiness or headaches that result from hormonal changes., though of course they're not sure-fire signs of pregnancy.

The results of any pregnancy tests you may take in the two weeks following embryo transfer will not be conclusive. That's why the earliest recommended time to take a pregnancy test is 14 days after the embryo is transferred the uterus — in other words, not until the end of the 2WW. By that time, a urine test or blood test for human chorionic gonadotropin (hCG) can determine whether you're pregnant or not.

A blood test will give a more accurate result than a home urine test. If the first test is positive for levels of hCG that indicate you're pregnant, a second test is usually performed two days later to be sure your hCG levels are increasing, which is further evidence that you're pregnant.

Updated August 2014