Pregnancy Calendar: Week Twenty Seven

Be prepared! You are entering your third trimester. Your baby looks like it will at birth; just thinner and smaller. Your baby will be growing steadily from now until week thirty six.

You may have noticed that we have added a new section in the column at right called "Born This Week". You may give birth anytime from this week on and your baby will have a good chance of survival. Of course, the closer your baby gets to term, the better its chances are. Follow the link to premature labor if you are worried that your baby may be coming too soon! Your doctor will tell you how your baby is developing, but you might want to begin preparing yourself for what to expect when the big day comes.

Term is usually considered two weeks before to two weeks after week forty. Only five percent of babies are actually born on their estimated due dateSometimes abbreviated to EDD, or referred to as the Estimated Date of Delivery. The EDD is calculated as 280 days after the first day of the last menstrual period.
Visit our comprehensive glossary for more pregnancy terms and definitions.
. If your baby is born this week it would have about an eighty five percent (17 in 20) chance of survival.

Growing Baby!
  • Size & Weight
  • 14.4 in (36.6 cm)
  • 1lb 15 oz (875 gr)
  • Use our fetal development chart to monitor the growth of your baby!

External details

Your baby's skin is red and very wrinkled. It looks like it has lost a lot of weight. But in fact the reverse is true and it is wrinkled in anticipation of depositing large quantities of fat before it is born. Your baby's skin is protected from the amniotic fluidThe liquid, which is produced by both the fetal membranes and the fetus that surrounds the baby during pregnancy. The liter of fluid at term serves to protect the fetus during pregnancy and also provide active chemical exchange.
The amniotic fluid consists of maternal and fetal plasma in varying concentrations. The pH of the fluid is almost neutral and clear, although lipids and desquamated fetal cells can make it cloudy.
Visit our comprehensive glossary for more pregnancy terms and definitions.
and nourished by a layer of waterproof vernix caseosaA gray-white waxy substance consisting of sebaceous gland secretions, lanugo and epithelial cells that covers the fetus during the last part of the pregnancy. It is thought to protect the skin of the baby from being submerged in the amniotic fluid as well as providing warmth and heat regulation to the undeveloped fetus.
Visit our comprehensive glossary for more pregnancy terms and definitions.

Your changing body

Your body is manufacturing increased levels of cholesterol to support the pregnancy hormonesA complex chemical substance created in a part or organ of the body. When released it initiates or regulates activity in an organ or group of cells in another part of the body.
Hormones secreted by endocrine glands are transported through the bloodstream to their target organ. The amount of hormone secreted is regulated either by other hormones, by neurotransmitters, or simply when an excess of the organ's activity indicates a need to reduce the amount of the hormone produced.
Other hormones are produced locally by the organs themselves and are common in the digestive tract.
Visit our comprehensive glossary for more pregnancy terms and definitions.
, such as progesteroneOne of the two naturally occuring female hormones (the other is estrogen) used to regulate and maintain the pregnancy. Produced first by the corpus luteum in the ovary, production is subsequently taken over by the placenta as it develops. During pregnancy a mother's production of progesterone ten times the level it was prior to conception. Progesterone and estrogen are responsible for giving many mothers a sense of tranquility, shiny hair and glowing skin.
Visit our comprehensive glossary for more pregnancy terms and definitions.
. These hormones are now being manufactured predominantly by the placentaThe placenta is a large disk shaped membrane responsible for providing nourishment to the fetus during pregnancy. It consists of three parts, the fetal part made up from the chorion membrane surrounding the fetus, the maternal part, formed from the decidua basalis layer of the uterine lining, and the intervillous space between the two plates. It is connected to the fetus by the umbilical cord and consists of tissue from both the mother and the embryo.
Its function is complex. It has been described as a simple organ that combines the functions of a kidney-dialysis machine, heart and lung machine and intravenous drip. It consists of enormous numbers of blood vessel branches that permit the exchange of nutrition and oxygen, from the mother's bloodstream to the fetus and the removal of wastes to the mother to be excreted. The placenta's remarkable quality is that it does so without the blood of the mother mixing with that of the baby.
It also is responsible for the production of vital hormones including, estrogen, progesterone, and human chorionic gonadotropin. After birth, the placenta is delivered, and is sometimes referred to as the afterbirth.
Visit our comprehensive glossary for more pregnancy terms and definitions.

Born this week

Pregnancy Tip!
  • Rest during the day by lying on your left side. Lying on your side increases circulation and reduces swelling.

Your baby has an eighty five percent chance of survival. In fact, it looks a lot like it would at full term; just smaller and thinner. This is because your baby still hasn't deposited enough fat to keep warm and it would have to be placed in an incubator.

Inside your baby is lacking surfactant, a greasy substance that prevents your baby's lungs from sticking and helps your baby breathe so your baby would require artificial respiration.

A liver, brain and immune system that aren't yet fully developed, make your baby susceptible to infections that a full term baby would easily fight.

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