Sunday July 15, 2018
A momentous meeting has taken place inside you – a single sperm has broken through the tough outer membrane of your egg and fertilized it. Several days later, the fertilized egg arrived in the uterus and started burrowing into the lining. A baby is in the making!
Your little one is just a tiny ball (called a blastocyst), consisting of several hundred cells that are multiplying madly. The part of it that will develop into the placenta has started producing the pregnancy hormone hCG (human chorionic gonadotropin), which tells your ovaries to stop releasing eggs and triggers increased production of estrogen and progesterone. These hormones keep your uterus from shedding its lining – and its tiny passenger – and stimulate the growth of the placenta. Meanwhile, amniotic fluid is beginning to collect around the ball of cells in the cavity that will become the amniotic sac. This fluid will cushion your baby in the weeks and months ahead.
Right now, your little blastocyst is receiving oxygen and nutrients (and discarding waste) through a primitive circulation system made up of microscopic tunnels that connect your developing baby to the blood vessels in your uterine wall. The placenta won’t be developed enough to take over this task until the end of next week.
Around the end of this week, you may be able to see a positive result on a home pregnancy test. If the result is negative, don’t assume you’re not pregnant – you may have just tested too early. (Tests are more likely to give an accurate result if you wait a few days to a week after you miss your period.) Wait a few days, and if you still haven’t gotten your period, test again. If another week or more goes by and you still haven’t gotten your period or a positive result, make an appointment to see your doctor or midwife.