Pregnancy Calculator by Week, Pregnancy Trimester, iiQ8 health
| Week | Trimester | Important Milestones |
| Week 1 | first trimester | |
| Week 2 | first trimester | |
| Week 3 | first trimester | Baby conceived |
| Week 4 | first trimester | Pregnancy test positive |
| Week 5 | first trimester | |
| Week 6 | first trimester | Heartbeat detectable by ultrasound |
| Week 7 | first trimester | |
| Week 8 | first trimester | |
| Week 9 | first trimester | |
| Week 10 | first trimester | |
| Week 11 | first trimester | |
| Week 12 | first trimester | |
| Week 13 | second trimester | Miscarriage risk decreases |
| Week 14 | second trimester | |
| Week 15 | second trimester | |
| Week 16 | second trimester | |
| Week 17 | second trimester | |
| Week 18 | second trimester | Baby begins making noticeable |
| Week 19 | second trimester | movements, can hear sounds, |
| Week 20 | second trimester | and gender can be found out. |
| Week 21 | second trimester | |
| Week 22 | second trimester | |
| Week 23 | second trimester | Premature baby may survive |
| Week 24 | second trimester | |
| Week 25 | second trimester | |
| Week 26 | second trimester | |
| Week 27 | second trimester | |
| Week 28 | third trimester | Baby can breathe |
| Week 29 | third trimester | |
| Week 30 | third trimester | |
| Week 31 | third trimester | |
| Week 32 | third trimester | |
| Week 33 | third trimester | |
| Week 34 | third trimester | |
| Week 35 | third trimester | |
| Week 36 | third trimester | |
| Week 37 | third trimester | |
| Week 38 | Full Term | Full Term |
| Week 39 | Full Term | |
| Week 40 | Full Term | |
| Week 41 | Full Term | |
| Week 42 | Full Term |
Note: The results of this calculator are estimations based on averages for single pregnancy. The results for twin pregnancy or multiple pregnancy are different.
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#Pregnancy Term & Due Date
Pregnancy is a term used to describe a woman’s state over a time period (~9 months) during which one or more offspring develops inside of a woman. Childbirth usually occurs approximately 38 weeks after conception, or about 40 weeks after the last menstrual period. The World Health Organization defines a normal pregnancy term to last between 37 and 42 weeks. During a person’s first OB-GYN visit, the doctor will usually provide an estimated date (based on a sonogram) at which the child will be born, or due date. Alternatively, the due date can also be estimated based on a person’s last menstrual period.
While the due date can be estimated, the actual length of pregnancy depends on various factors, including age, length of previous pregnancies, and weight of the mother at birth.1 However, there are still more factors affecting natural variation in pregnancy terms that are not well understood. Studies have shown that fewer than 4% of births occur on the exact due date, 60% occur within a week of the due date, and almost 90% occur within two weeks of the due date.2 As such, while it is possible to be fairly confident that a person’s child will be born within about two weeks of the due date, it is currently not possible to predict the exact day of birth with certainty.
WEEK 1 & 2
Baby Conceived
It’s ovulation time. If sperm and egg meet, you’re on your way to pregnancy.
WEEK 3
Implantation occurs
Your baby is a tiny ball of several hundred cells that are rapidly multiplying and burrowing into the lining of your uterus. The cells that become the placenta are producing hCG, the pregnancy hormone. It tells your ovaries to stop releasing eggs and keep producing progesterone. Once there’s enough hCG in your urine, you’ll get a positive pregnancy test result.
WEEK 4
Positive Pregnancy Test
Your baby is an embryo made up of two layers, the hypoblast and the epiblast. The primative placenta is developing and preparing to provide nutrients and oxygen to your growing baby. The amniotic sac is developing and will surround and protect your baby while it continues to grow.
WEEK 5
Your embryo is now made up of three layers, the ectoderm, the mesoderm and the endoderm which will later form all the organs and tissues. You might start to feel the first twinges of pregnancy such as tender breasts, frequent urination, or morning sickness
WEEK 6
Heartbeat detectable by ultrasound
Your baby’s heart is beating about 160 times a minute and the nose, mouth and ears are taking shape. Lungs and digestive system are forming organs.
WEEK 7
Your baby is forming hands and feet. Key organs like the stomach, liver and esophagus are beginning to form. Your uterus has doubled in size. The umbilical cord is transferring blood and waste between baby and mother.
WEEK 8
The respiratory system is forming now. Breathing tubes extend from the throat to the branches of the developing lungs.
WEEK 9
Your baby is nearly an inch long now. If you watch closely, you may see your baby move if you have an ultrasound done
WEEK 10
Your baby’s organs are growing and beginning to mature. The baby’s head comprises half the length of the body.
WEEK 11
Fingers and toes have separated and the bones are beginning to harden. External genitalia has almost completely formed.
WEEK 12
The kidneys can now secrete urine and the nervous system is maturing. You baby may be curling all 10 toes, practicing opening and closing fingers and sucking a thumb. And mom should have gained from 2-5 lbs.
WEEK 13
Miscarrige risk decreases
Your baby now has unique fingerprints and the kidney and urinary tract are completely functional, that means she’s peeing. And if you are having a girl, her ovaries are already full of thousands of eggs.
WEEK 14
Your baby’s facial muscles are getting a workout as he squints, frowns, grimaces and practices his first smile for you.
WEEK 15
Your baby is looking more like a baby with legs growing longer than the arms and all her limbs moving. The ears are properly positioned on the side of her head and the eyes are moving from the side of the head to the front of the face. At your doctor’s visit, he should offer you a quad screening test to check for Down’s syndrome or other chromosomal abnormalities.
WEEK 16
Baby’s heart is pumping about 25 quarts of blood each day. His eyes are working and moving side to side even though the eyelids are still sealed. Mom will have a “pregnancy glow” due to increased blood supply.
WEEK 17
Baby’s skeleton is changing from soft cartilage to bone and her heart is now regulated by her brain. She’s practicing her sucking and swallowing skills in preparation for that first suckle at your breast or the bottle. Mom’s breasts may have increased a full bra size.
WEEK 18
Gender reveal time
If you’re having a girl, her uterus and fallopian tubes are formed and in place. If you’re having a boy, his genitals are noticeable now but he may hide them during an ultrasound. Are you feeling kickes and punches? Baby’s hearing is also developing, so you may want to start talking to your baby.
WEEK 19
Baby’s brain is designating specialized areas for his 5 senses – vision, hearing, taste, smell and touch. A waxy protective coating called the vernix caseosa is forming on his skin to prevent wrinkling.
WEEK 20
Your baby weighs about 10 ounces and is the size of a small banana. Her uterus is fully formed this week and she may have tiny primitive eggs in tiny ovaries now. His testicles are waiting for the scrotum to finish growing and will begin their descent soon. Mom can expect to gain about 1/2 lb per week for the rest of her pregnancy.
WEEK 21
Feel all that moving and shaking going on! Baby’s arms and legs are in proportion now and movements are much more coordinated. Bone marrow is now helping the liver and spleen produce blood cells. The intestines are starting to produce meconium, the thick tarry looking stool first seen in baby’s diaper.
WEEK 22
Senses are growing stronger. Now she can hear your heart beat, your breathing and digestion. Sense of sight is becoming more fine-tuned and he can preceive light and dark. Hormones are now developing which will the organs the commands they need to operate.
WEEK 23
Premature baby may survive
Baby’s organs and bones are visible through his skin, which has a red hue because of the developing veins and arteries beneath. He’ll become less transparent as his fat deposits fill in. Baby is also developing surfactant which will help the lungs inflate if baby is born prematurely
WEEK 24
Baby’s face is almost fully formed complete with eyelashes, eyebrows and hair. Right now her hair is white because there’s no pigment yet. Between now and 28 weeks, the doctor should send mom for a glucose screening test for gestational diabetes.
WEEK 25
Baby is gaining more fat and looking more like a newborn. Hair color and texture is in place. His lungs are maturing and preparing for that first breath. You might feel the baby having hiccups.
WEEK 26
Brain-wave activity is on high That means baby can hear noises and respond to them with an increase pulse rate or movement. Eyes are beginning to open but they don’t have much pigmentation. That will develop over the next couple months and may even continue to change until she’s about 6-months-old.
WEEK 27
Start talking to your baby
Baby may recognize both your and your partner’s voices. This is the time to read and even sing to your baby. She now has taste buds so when you eat spicy food, your baby will be able to taste the difference in the amniotic fluid. Her mealtime comes about two hours after yours. Feel some belly spasms? Those are likely hiccups from that spicy food. It doesn’t bother the baby as much as you. Baby also has settled in to a regular sleep cycle, but it may be different from mom’s.
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WEEK 28
During the third trimester the brain triples in weight adding billions of new nerve cells. Senses of hearing, smell and touch are developed and functional. Your baby is having different sleep cycles, including rapid eye movement. That means she’s dreaming.
WEEK 29
Baby can breathe
Baby’s bones are soaking up lots of calcium as they harden so be sure to consume good sources of calcium. We recommend taking Nordic Naturals and Fairhaven Health supplements.
WEEK 30
Baby’s brain is taking on characteristic grooves and indentations to allow for an increased amount of brain tissue. Bone marrow has taken over the production of red blood cells. This means she’ll be better able to thrive on her own when she’s born Baby is now weighing about 3 lbs and is 11 inches.
WEEK 31
Baby’s brain is developing faster than ever and he’s processing information, tracking light and perceiving signals from all five sense. She’s probably moving a lot, especially at night when you’re trying to sleep. Take comfort that all this activity means your baby is healthy. Mom may start feeling some Braxton Hicks contractions.
WEEK 32
Baby can focus on large objects not too far away; toenails and fingernails have grown in along with real hair. He’s practicing swallowing, breathing, kicking and sucking. All key skills for thriving after birth.
WEEK 33
Immune system is maturing
The bones in your baby’s skull are still pliable which makes it easier for her to fit through the birth canal. Your uterine walls are becoming thinner allowing more light to penetrate your womb. That helps baby differentiate between night and day.
WEEK 34
Baby’s fat layers are filling her out and will help regulate body temperture when she’s born. If your baby is a boy, the testicles are making their way down from the abdomen to the scrotum.
WEEK 35
Kidneys are fully developed and her liver can process some waste products. Most of her physical development is complete. She’ll spend the next few weeks gaining weight and adding baby fat. Baby is settling lower into the pelvis preparing for delivery and this is called “lightening”.
WEEK 36
Hopefully your baby is in a head-down position. If not, your practitioner may suggest an external cephalic version to manipulate your baby into a head down position. The vernix caseosa has now disappeared.
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WEEK 37
Baby is considered full term
Baby is taking up most of the room in your womb so he’s only kicking and poking you, no more somersaults. Baby is sucking her thumb, blinking eyes and inhaling and exhaling amniotic fluid.
WEEK 38
Baby’s eyes right now are blue, gray or brown but once they’re exposed to light they may change color or a shade. The lanugo, the fine downy hair that covered his body for warmth is falling off in preparation for delivery. Her lungs have strenthened and her vocal cords have developed. That means she’s ready for her first cry.
WEEK 39
Baby is ready to make his debut. He’s adding more fat as his pinkish skin turns white or white-grayish. He won’t have his final pigment until shortly after birth.
WEEK 40
This is the official end of your pregnancy but because due dates are just a calculation he might be “late.” No need to worry, your body knows the right time to go into labor, or your doctor may suggest you be induced. At birth your baby’s eye sight is a little blurry since central vision is still developing. Just say hello and he’ll recognize your voice.
Pregnancy Detection
Pregnancy can be detected either by using pregnancy tests or by the woman herself noticing a number of symptoms, including a missed menstrual period, increased basal body temperature, fatigue, nausea, and increased frequency of urination.
Pregnancy tests involve the detection of hormones that serve as biomarkers for pregnancy and include clinical blood or urine tests that can detect pregnancy from six to eight days after fertilization. While clinical blood tests are more accurate, and can detect exact amounts of the hormone hCG (which is only present during pregnancy) earlier and in smaller quantities, they take more time to evaluate and are more expensive than home pregnancy urine tests. It is also possible to get a clinical urine test, but these are not necessarily more accurate than a home pregnancy test, and can potentially be more costly.
Pregnancy Management
There are a number of factors that need to be considered during pregnancy, many of which are highly dependent on the individual’s situation, such as medication, weight gain, exercise, and nutrition.
Medication:
Taking certain medications during pregnancy can have lasting effects on the fetus. In the U.S., drugs are classified into categories A, B, C, D, and X by the Food and Drug Administration (FDA) based on potential benefits vs. fetal risks. Drugs that have positive benefits for the mother with low risk to the fetus are classified as category A, while drugs with proven, significant fetal risks that outweigh potential benefits to the mother are classified as category X. A person that is pregnant should consult their doctor regarding any medications they plan to use during their pregnancy.
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Weight gain:
Weight gain is a largely inevitable and necessary aspect of pregnancy that varies between people. It affects many aspects of fetal development, such as the weight of the baby, the placenta, extra circulatory fluid, and its fat and protein stores. Weight management merits consideration because insufficient or excessive weight gain can have negative effects for both mother and fetus, including the need for cesarean section (C-section) and gestational hypertension. While the values vary between women, the Institute of Medicine recommends an overall pregnancy weight gain of 25-35 pounds for women who are considered “normal” weight (BMI 18.5-24.9), 28-40 pounds for those considered underweight (BMI < 18.5), 15-25 pounds for those considered overweight (BMI 25-29.9), and 11-20 pounds for those considered obese (BMI > 30).3 Our Pregnancy Weight Gain Calculator is based on the Institute of Medicine recommendations.
Exercise:
Studies indicate that aerobic exercise during pregnancy helps to improve or maintain physical fitness as well as possibly decreasing the risk of C-sections. Although it varies between women, regular aerobic and strength-conditioning exercise are often recommended for pregnant women, and women who exercised regularly before pregnancy, who have uncomplicated pregnancies, should be able to continue high-intensity exercise programs.4 The American College of Obstetricians and Gynecologists suggests that given an uncomplicated pregnancy, fetal injuries are unlikely to occur as a result of exercise. Nevertheless, caution is advised, and a pregnant woman should consult their doctor if any of the following symptoms present: vaginal bleeding, shortness of breath, dizziness, headache, calf pain or swelling, amniotic fluid leakage, decreased fetal movement, preterm labor, muscle weakness, or chest pain.5
Nutrition:
Nutrition during pregnancy is particularly important for the health of the mother and baby. Pregnancy requires different nutritional considerations than a person would have in a non-pregnant state due to increased energy and specific micronutrient requirements.6
Certain vitamins such as Vitamin B9, also known as folic acid, can help decrease the risk of certain defects, while other nutrients such as DHA omega-3 that is necessary for proper brain and retinal development cannot be produced efficiently by infants, and can only be obtained through the placenta during pregnancy, or in breast milk after birth. There are many other micronutrients that aid proper fetal development, and there exist myriad sources of information on what pregnant women should or shouldn’t eat or do. All of the information can be different to sift through and can vary from person to person. Pregnant women should consult their doctors and/or dietitian to help determine the best course of action for their own specific needs.