13 days pregnant: your pregnancy week by week


MNT Knowledge Center

During week 13 of the pregnancy, kids organ systems still mature and develop. Just like other earlier days, week 13 isn’t any exception with regards to rapid growth and big developmental strides.

Additionally to fetal development and growth, your placenta keeps growing and today weighs roughly 1 oz. You will probably possess a 1-2 lb placenta once the baby comes into the world.1

This MNT Understanding Center feature belongs to a number of articles on pregnancy. It possesses a review of each stage of being pregnant, what to anticipate, and insights into the way your baby is developing. Check out another articles within the series:

First trimester: fertilization, implantation, week 5, week 6, week 7, week 8, week 9, week 10, week 11, week 12.

Second trimester: week 13, week 14, week 15, week 16, week 17, week 18.

Additionally, you will see introductions in the finish of some sections to the recent developments which have been included in MNT’s news tales. Also consider links to details about related conditions.

Signs and symptoms at 13 days pregnant

At this time of the pregnancy, you will continue to experience physical pregnancy signs and symptoms for example:1

Image of a woman clutching her chest.
At this stage of your pregnancy, you may begin to experience physical symptoms such as heartburn.

  • Breast changes and tenderness
  • Lessened fatigue
  • Heartburn or gas
  • Food cravings and/or aversions
  • Heartburn, indigestion or constipation
  • Dizziness
  • Faintness
  • Visible veins.

Remember that pregnancy increases the chance of urinary system infections from week 6 to week 24, therefore if your signs and symptoms aren’t simply in the pregnancy and also you suspect contamination, consult with a physician about treatment.2

Your hormones at 13 days pregnant

During your pregnancy, you’ll experience variations in a few hormones that lead to most of the pregnancy signs and symptoms you might experience. Following implantation from the fertilized egg, the body starts to secrete a hormone known as human chorionic gonadotrophin (hCG) – the hormone accustomed to identify pregnancy.3 This substance can also be accountable for controlling oestrogen and progesterone and plays a role in frequent peeing.3

Initially created through the corpus luteum, progesterone increases during your pregnancy and still does so before the birth of the baby.3 At the begining of pregnancy, progesterone accounts for growing uterine bloodstream flow, creating the placenta which stimulates the development and nutrient manufacture of the endometrium (lining from the uterus).3

Progesterone also plays a vital role in fetal development, stopping premature labor and lactation, in addition to strengthening the pelvic wall muscles to organize the body for labor.

Additionally to progesterone, the placenta is essential in secreting vital hormones while pregnant for example:3

Human placental lactogen: this substance is thought to be accountable for mammary gland growth that’ll be essential for lactation following a birth of the baby. Furthermore, it plays a part in growing nutrient levels inside your bloodstream, fundamental to the progression of your child.

Corticotrophin-releasing hormone: this substance isn’t just accountable for figuring out how lengthy you’ll be pregnant, but in addition for kids development and growth. Later during pregnancy, the increase in both corticotrophin-releasing hormone and cortisol both completes fetal organ development and offers mom having a rush of cortisol that’s been associated with maternal attentiveness, growing mom-baby bond.

Another vital hormone during pregnancy is oestrogen, which accounts for fetal organ development, placental growth and performance and mammary gland growth.3 Furthermore, oestrogen is required for that regulating other hormones created while pregnant.3

Due to the increase in progesterone and oestrogen, you might experience some uncomfortable pregnancy signs and symptoms for example moodiness and morning sickness.3 Another hormone, relaxin, may cause physical signs and symptoms for example pelvic discomfort, balance difficulties and constipation because of its role in relaxing maternal muscles, ligaments and joints.3

Dna testing at 13 days pregnant

You should consult with your medical provider to find out if dna testing and certain types of prenatal screening is worth considering. Some prenatal screening tests can start around 10 days pregnancy.4

From days 11-14, an ultrasound might be acquired to judge kids nuchal translucency – the quantity of fluid underneath the skin behind the newborn’s neck.4 This will be significant in testing for many health conditions that could affect your child for example Lower syndrome.4

You will find three bloodstream tests provided to women throughout their pregnancy to screen for various genetic abnormalities including Lower syndrome, Trisomy 18, and spina bifida.4

These tests include:4

  • Sequential integrated screen: between weeks 10-13 and again during weeks 15-20, this screening test may be recommended to test the maternal blood for the six fetal proteins found in maternal blood circulation. This test is capable of identifying 92% of Down syndrome pregnancies. The first portion of this test is completed in combination with a nuchal translucency ultrasound (as mentioned above).
  • Serum integrated screen: as in the sequential integrated screen, maternal blood is tested during weeks 10-13 and again during weeks 15-20 for the six fetal proteins found in maternal blood circulation. This test is capable of identifying 88% of Down syndrome pregnancies. This test is typically carried out in cases where a nuchal translucency ultrasound is unavailable.
  • Quad marker screen: obtained during weeks 15-20, the quad marker screen tests maternal blood for four circulating fetal proteins. This test is capable of identifying 79% of Down syndrome pregnancies. Women who did not get the first portion of the serum and sequential tests (as above) are eligible to undergo this testing. This test is also the second test obtained during the sequential and serum screening tests.

Baby’s development at 13 weeks pregnant

Image of fetus at 13 weeks pregnant.
By the time you are 13 weeks pregnant, your baby’s salivary glands have started functioning.

At 13 weeks pregnant, there are many changes in your baby’s development. Developments that are underway include:1,5

  • Head and neck: salivary glands start functioning and vocal cords continue to develop
  • Heartbeat: the heartbeat can now be heard with an external Doppler
  • Chest: lungs continue to mature, amniotic fluid is inhaled and exhaled
  • Abdomen: spleen and liver remove old red blood cells and produce antibodies, intestines continue to migrate from umbilical cord to the abdomen
  • Pelvis: sex organs fully visible
  • Limbs: arms proportional with increasingly functional hands, though legs remain short
  • Skin: sweat glands are present, body hair is growing, muscles and nervous system are maturing
  • Other: bone marrow is producing white blood cells, the pituitary gland is manufacturing hormones.

Changes in lifestyle at 13 days pregnant

Just like earlier days, it’s easy to discover there are many lifestyle modifications that should be made while pregnant which after delivery.

Overall health

While pregnant, you will have to take proper care of your and yourself developing baby. Don’t consume alcohol or smoke while pregnant, and steer clear of other toxins for example drugs during this period.6 Make sure to discuss all medications you’re taking with your medical provider to actually should continue use while pregnant.6

To nourish your and yourself baby, make certain you consume a healthy diet plan and have a good prenatal vitamin.6 A different way to keep your health while pregnant is to buy physical exercise. Consult with your medical provider regarding your current or preferred exercise program to make certain it’s safe.


Even though it is safe to consume fish while pregnant, it’s suggested that you simply limit your intake to eight-12 oz. of seafood each week.2,7,8

A few examples of fish which are safe to eat while pregnant include shrimp, salmon, canned light tuna (note: mercury varies can to can), pollock, cod, catfish and anchovies.2,8 If you are considering eating albacore tuna and tuna steak, it’s suggested that you simply limit consuming this fish to six oz. each week.7,8

Do not eat shark, swordfish, tilefish and king spanish mackerel during pregnancy, because they contain high amounts of mercury which may be dangerous for your baby’s brain and central nervous system.7 If eating use a non-commercial source – a fish you and your family caught, for instance – make sure to seek advice from the neighborhood health government bodies the waters that was caught are secure.7

Always make certain the food is fully cooked and never raw or undercooked. Also avoid uncooked smoked or pickled fish.7 Furthermore, you should avoid unpasteurized soft cheese, refrigerated paté, raw or undercooked meat and chicken, cold cut deli meat, foods that contains raw eggs (Caesar dressing, etc) and unpasteurized juice, milk and eggnog.7

Require a boost? Caffeine is alright while pregnant but ought to be consumed moderately. Keep your caffeine consumption all sources at or below 300 milligrams daily.7

Baby’s size at 13 days pregnant

Two peaches.

At 13 days pregnant, your child is how big a peach.

Around 2.5 inches, your child has become about how big a peach.1

Their mind has become more in balance with all of those other body, using its size creating in regards to a third of their overall frame.1

Your child can move their arms and could now have the ability to take their thumb within their mouth.1

For those who have queries about your pregnancy, make sure to contact your medical provider.

Call your physician if you’re experiencing signs and symptoms of the ectopic pregnancy or miscarriage for example vaginal bleeding or passage of tissue, dripping vaginal fluid, feeling faint or dizzy, low bloodstream pressure, rectal pressure, shoulder discomfort and severe pelvic discomfort or cramping.