13 weeks pregnant

By BSc, MSc (embryologist) and BA, MA (fertility counselor).
Last Update: 11/04/2014

During this week you’ll be gaining weight and your body will begin to change its physical appearance: the waist loses its characteristic form and it seems to be more rounded. It’s possible that you may have to buy new clothes, since the ones you used to wear won’t fit anymore. You’ll also notice that the volume of your breasts has increased, you may feel some pain and the aureole will get bigger and darker.

Furthermore, discomforts may increase: apart from acidity and nausea, you’ll feel some discomfort due to the enlargement of the uterus; you may feel some cramps at the ligaments in charge of joining the uterus with the abdominal wall. Other possible symptoms during this week are: a slower intestinal transit, smooth muscles and those muscles that don’t have voluntary movement become slower. That's what happens with the intestines, the intestinal transit is slower, and therefore you’ll need more time to digest food. Add fibre to your diet to counteract some of these symptoms.

Development of the embryo week 13

The embryo's most important changes during this week are: from this week until week 25 he’ll grow at an extremely quick pace, and after all the structures are formed he’ll just need time to develop them completely.

The face acquires a rounded more common shape, the eyes, between which there was a big space, get a bit closer and the ears rise reaching almost their definitive location, since when they formed, they were very low.

An intestine primordium is already formed, named bowel loops. At the beginning they are located in the umbilical cord, but during this week they reach their position inside the abdominal cavity.

At the end of this week the embryo size is 8.5 mm long and its weight ranges between 15 and 20 grams. However, if the weight of your child varies between 13 and 25 grams don’t panic, it’s also normal.

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 Neus Ferrando Gilabert
Neus Ferrando Gilabert
BSc, MSc
Bachelor's Degree in Biology from the University of Valencia (UV). Postgraduate Course in Biotechnology of Human Assisted Reproduction from the Miguel Hernández University of Elche (UMH). Experience managing Embryology and Andrology Labs at Centro Médico Manzanera (Logroño, Spain). More information about Neus Ferrando Gilabert
Adapted into english by:
 Sandra Fernández
Sandra Fernández
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

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