Pregnancy week 6

Filed under First trimester · Pregnancy Week to Week editorial team

By week 6 of pregnancy, morning sickness, tenderness of the breasts, and darker areolas are sure fire signs of pregnancy. Although an outsider would not be able to tell, women often have trouble getting into their jeans at this point. Sometimes however, the first trimester brings about a weight loss rather than the typical 5 pound weight gain. This is all completely normal unless the weight loss is caused by a condition known as hyperemesis gravidarum, or extreme morning sickness. Women with this pregnancy complication experience violent nausea and vomiting throughout the early terms of their pregnancy. Since the condition can cause dehydration, electrolyte deficiencies, and an unusual amount of weight loss, the mother sometimes needs to be hospitalized. Typically, the baby will not be harmed if the condition is looked after. Physicians agree that younger maternal age, obesity, and first time pregnancies are often the most at risk for this condition. Also, the doctor will probably advise supplementary vitamins after hospitalization to make certain that the baby receives the appropriate amount of nutrients.

During pregnancy week 6, an ultrasound will indicate the baby’s “crown-rump length.” This is the measured length between the top of the baby’s head to the buttocks. At week 5, this measurement can be anywhere from 2 to 5mm. At this point, the fetus looks like a blob with dark spots where the eyes, nostrils, and ears will eventually develop. Arms and legs will start to emerge from the tiny buds on the body and the hands and feet will have webbing between the fingers and toes. Also during this time, the baby will start to move on its own and respond to touch. Since the central nervous system is connecting the muscles with the limbs in the body, the baby’s reflexes can also be noted. At pregnancy week 6, the baby’s heartbeat, although still probably inaudible through ultrasound, is beating at around 140 beats per minute. This allows for blood to begin circulating through the baby’s body. From this point on, following the baby’s development will be a fascinating lesson on the complexity of the human body.

Current guidance (today's medical sources): By week six the embryo is developing facial features and small limb buds, and the heartbeat — often visible on an early ultrasound — typically falls in the range of about 100 to 160 beats per minute. Nausea (so-called morning sickness, which can happen at any time of day) and food aversions are common, though their severity varies. Persistent, severe vomiting that prevents keeping fluids down should be discussed with a provider, as it can indicate hyperemesis gravidarum.

Sources: NHS — 6 weeks pregnant; Mayo Clinic — Fetal development: The 1st trimester; ACOG — Pregnancy (FAQ / month-by-month). Informational only. See our sources & medical-review policy.

Informational only — not medical advice. Pregnancy Week to Week is a general educational reference. It is not a substitute for professional medical care, diagnosis, or treatment. Every pregnancy is different: always consult your doctor, midwife, or other qualified healthcare provider about your own pregnancy, and never disregard or delay professional advice because of something you read here. In an emergency, contact your maternity unit or local emergency number immediately.