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Twin Pregnancy Week By Week Guide: A Personal Belly Gallery And Growth

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Twin Pregnancy Week By Week Guide
Twins.adorable with Florian and Mathieu

Before we get started with anything, let’s just take a moment and say this- Wow! twin pregnancy Week-By-Week? You’ve surely won a jackpot Week-By-Week get ready to invite twins in just a few months!

Now that we’ve sailed the boat, let’s not get carried away and make this twin pregnancy Week-By-Week double trouble, but, have the trimester sail in much more comfort and ease. We understand how challenging yet strange a twin pregnancy belly can be, so, to help you out with your journey, Parenthoodbliss has taken a step ahead and collaborated with four amazing accounts of mama bears (Katie, Andre Carzi, Kelly, and the social media account Week-By-Week twinss.adorable), who have been kind enough to share their personal pictures with our blissful family, helping to make the twin pregnancy journey more comforting.

Without wasting any more time, let’s cut to the chase and know how are twins in the womb week-by-week.

Twin Pregnancy Week By Week
Katie’s twins, Oliver and Evelyn

Without wasting any more time, let’s cut to the chase and know what you can expect when you’re expecting twins!

Twin Pregnancy: Week By Week Guide

Twin pregnancy
Andre Carzi expecting Max and Leo

Andre Carzi expecting Max and Leo

Here is your twin pregnancy week-By-week guide for everything you can expect or feel like until full term;

First Trimester: Pregnant With Twins -

Pregnant With Twins Parenthoodbliss
Kelly and her twin pregnancy

Symptoms And Development

This is when you’re being more cautious about determining your pregnancy with the help of the best pregnancy test and confirm the pregnancy and officially head towards your first trimester! Nevertheless, when it comes to confirming whether you’re carrying twins can only be done so by your healthcare provider, often during an ultrasound scan around 12 weeks.

1-4 Weeks Pregnant With Twin Baby

Twins in the Womb Week-By-Week Symptoms

Symptoms –

  • Light implantation bleeding can be experienced when the fertilized eggs get attached to the uterine lining after two weeks of fertilization
  • Breast tenderness due to the changes in the hormones, that might get a little intense with two babies. All thanks to the extra hCG or human chorionic gonadotropin produced by the body.

Twin Pregnancy Belly Week-by-Week Size Development-

  • The twins would be either ‘Fraternal twins,’ that is when the two eggs are fertilized by different sperms, creating two zygotes and then become an embryo (not identical); or ‘Identical twins,’ that is when a fertilized egg and the zygote splits early during pregnancy, forming embryos (Identical and same-sex)
  • Implanted and dividing rapidly at around two weeks after fertilization
  • At about three weeks, the placentas begin to form, providing nourishment and oxygen

5-8 Weeks Pregnant With Twin Baby

Twins in the Womb Week-by-Week Symptoms –

  • Around these weeks, you can expect to have frequent visits to the restroom due to the increase of blood in your body and the kidneys processing with additional fluid. Having said that, do not limit the intake of water, you don’t want to be dehydrated during your twin pregnancy!
  • Due to the increased levels of hCG and progesterone hormone, expect to experience fatigue. Have as much rest as you can!
  • Although a little too soon, some mom-to-be experience morning sickness this early, and when pregnant with twins, the case could get a little extreme

Twin Pregnancy Belly Week-by-Week Size Development –

  • During these weeks, the twins will start to develop their brain and spinal cords from their own neural tube
  • Sprouting of the little arms and legs by 8 weeks of the twin pregnancy
  • Both the babies will begin to form their heartbeats
  • By the end of 8 weeks of your twin pregnancy, the two babies will begin to develop major organs, including the genitals and lungs

9-13 Weeks Pregnant With Twin Babies

Twins in the Womb Week-by-Week Symptoms –

  • There will be an increase in the milk glands and fatty tissues, indicating that your breasts have begun to develop and be fuller for two babies! This is the best time to start preparing to buy comfortable nursing bras
  • Expect to experience an increase in vaginal discharge as a result of the increased level of hormones and blood in the body, anytime around 9 weeks or 10 weeks. It’s normal as long as it’s white or clear, and odorless. However, if they get itchy, burn, or have a bad smell, you must contact your doctor as it might indicate an infection

Twin Pregnancy Belly Week-by-Week Size Development –

  • During this week of your twin pregnancy, your babies will start developing their fingers, toes, and nails
  • The faces of the twins will also become less broad and more defined with eyelids, beginnings of a nose, upper lip, eyes, and tooth buds
  • The babies will now start producing urine into the amniotic sac

Second Trimester: Pregnant With Twins - Symptoms And Development

Second trimester twins Parenthoodbliss
Second Trimester: Pregnant With Twins - Symptoms And Development
Katie and her twins

When pregnant with twins, the moms-to-be can expect to have their belly show sooner in the second trimester.

14-17 Weeks Pregnant With Twins

Symptoms –

  • From 14 weeks of your twin pregnancy, expect to gain somewhere between 37 to 54 pounds. As per experts, you must only add about 600 calories to the daily diet
  • With the expanding uterus and belly, there will be a change in the posture that might cause lower back pain. To help with this, make sure to contact your healthcare provider for some safe stretches to ease the discomfort and strengthen the back muscles

Development –

  • By this week, the sex organs of the twins will develop and can even be seen on an ultrasound
  • Although the eyes of the twins are shut, by 16 weeks your babies will move their eyes behind the eyelids
  • Will grow eyebrows and eyelashes
  • You may experience the little one move

18-22 Weeks Twin Pregnancy

Symptoms –

  • By 18-22 weeks, it could be a little difficult to catch a goodnight’s sleep, thanks to your growing belly. To help, try to sleep on your side with a few pillows and a cushion between your knees
  • Due to the ever-growing twin pregnancy belly, the elastic tissues underneath your skin would weaken, causing stretch marks and making your skin itchy. Make sure to keep yourself well hydrated and moisturized
  • The increase in blood volume can prompt changes in your circulation, causing you to feel dizzy

Development –

  • Your little ones will now begin to suck their thumb as the sucking reflex develops during these weeks of the twin pregnancy
  • By 18 weeks, the twins will develop their sense of hearing
  • Both the babies will acquire a greasy, waxy coat on their skin called vernix that will protect them from the amniotic fluid
  • The babies will be covered with downy protective hair also known as the lanugo that will the vernix on the skin and protect them from the amniotic fluid

23-27 Weeks Pregnant With Twin Babies

Symptoms –

  • The mom-to-be may experience hot flashes during their twin pregnancy due to the change in hormones and metabolism. Make sure to wear comfortable clothes and stay hydrated throughout
  • Your blood pressure will be checked at all prenatal checkups to look out for a serious blood pressure disorder – preeclampsia, more common when carrying twins.

Development –

  • For the first time, the twins will start to form ridges on the palms and soles of their feet which will later become fingerprints and footprints
  • Expect your babies to now respond to any form of sound, such as your voice
  • By the 26th week, the lungs of the babies will start to produce surfactants that will help the air sacs to stay inflated
  • The little “children” will also develop the motion of grasping

Third Trimester: Pregnant With Twins - Symptoms And Development

Third trimester Parenthoodbliss
Katie’s Twin Pregnancy

By the third trimester, expect to feel more pains and aches and pains, especially during your twin pregnancy. You’re almost there!

28-32 Weeks Of Carrying Twins

Symptoms –

  • The mom-to-be can expect to experience hip and pelvic pain at around 31 weeks that will likely go away as the twins are born. Nevertheless, if you feel numb, make sure to consult your doctor right away
  • You may start to feel the Braxton hicks contractions this trimester, but this doesn’t necessarily mean that you’re in labor! On the contrary, these contractions can help your body prepare for the real deal
  • Extra blood flow can be expected in the pelvic region with the pressure of a larger uterus, resulting in hemorrhoids. During this time, make sure to eat foods rich in high fiber and take warm baths to aid the discomfort

Development –

  • At 28 weeks, the twins may be able to open and close their little eyes and sense changes in light
  • At 32 weeks of your twin pregnancy, the twins may shed the fine hair around their body
  • All thanks to the development of the brain, the twins can now control their body temperature and being less dependent on the amniotic fluid for warmth
  • The bones of the twins in this last trimester continue to harden, but still, have a soft skull to help them pass through the birth canal when having a vaginal delivery

33-36 Weeks Of Twin Pregnancy

Symptoms –

  • Due to the fluid retention, there can be swelling in your legs and feet. To help aid it, try to elevate your feet. On the other hand, if the swelling occurred suddenly, you must contact your doctor as it might be a sign of preeclampsia
  • Expect to feel tired more often, and it’s ok, having twins could be a little draining. Make sure to take naps in the afternoons and do some light exercise
  • There is a chance of deep vein thrombosis, especially when carrying twins. This happens if placed on bed rest by the doctor. Nevertheless, if you experience pain in the calf, redness, and warmth, consult your healthcare provider immediately to help minimize your risk of deep vein thrombosis.

Development –

  • The organs of the babies will continue to develop, including the lungs preparing to breathe outside the womb, the circulatory and musculoskeletal systems
  • During the last few weeks, the babies will continue to gain weight. While most twin babies are born smaller than singletons, expect their average weight to be around 5.1 pounds each

37-40 Weeks Twin Pregnancy

Symptoms –

  • Expect to snore during your naps due to the changes in the breathing pattern toward the end of your pregnancy. To aid, try wearing nasal strips or use a humidifier during the night
  • All thanks to the growing twin belly, it might get a little difficult to move around. Try and take smaller steps and take time off to relax more often

Development –

  • The development will still continue, such as their brain
  • Expect the twins to take their head-down position or the optimal position for a vaginal delivery. Nevertheless, in some cases, one of the twins might have their head down or both feet first
Twins.adorable (Florian and Mathieu)

Twin Pregnancy - Childbirth Or Labor When Expecting Twins Final Thoughts

In a few cases, a twin pregnancy is considered to be one with a “high risk” of preterm birth, that is, almost 50 percent are born before 37 weeks. In such cases, the doctor could recommend inducing labor before the due date in order to avoid any complications when pregnant with twins.

twins pregnancy
Andre Carzi and her partner expecting Max and Leo

Such was the case of @Andre Carzi;

Not all pregnancies are the same or easy. With my twin pregnancy, there was a lot to go through. I had lost around 8 kg by the 3rd month of my pregnancy and had bleeding in the 4th. I thought I might lose my babies after that episode. I was asked to lay in bed. Not only that, by the 5th month I then lost my job, and by 6th the doctor had said that my babies could be affected by some sort of Scheletrical disease as they were not growing up and I might have to give birth as early as possible.

Luckily, Max and Leo were so strong to resist till 36 weeks. I and Leo left the hospital after 12 days and Max remained in the NICU for 1 month. We were so lucky and I thank god every day for this!

Our twin pregnancy was so hard, but in the end, everything was ok and this is the most important thing 🧡”

Scaling through the weeks when pregnant with twins could be a task in most cases, where there is a higher chance of a cesarean section, and if no complications, a vaginal delivery. Whatever be the case, be assured that your healthcare provider will only help you with the best and the safest option.

Also, with twins, mama bears will require to spend a little more extra time in the hospital and wait until the doctors give a green light for you to head home with your little adorable twins!

On a closing note; the journey of being twin parents could be tough, but for all that matters, “as long as it’s done, it’s okay – your spouse/partner/whoever is helping isn’t going to do things the same way that you do – but as long as it’s done, it’s good enough. ie. Folding laundry or feeding the babies 💙 and that you’ve got this! It’s such a wild adventure that not everyone can relate to, so find your people and jump in!” – Katie

Twin Pregnancy - Childbirth Or Labor When Expecting Twins
Katie and her partner welcomed their little twins home

Twin Pregnancy Week By Week Guide FAQs

1) How will one know that they're having twins?

You can be sure of having twins when you hear a beat (or two!) during a vaginal ultrasound at around six weeks of pregnancy. However, to be accurate, you will have to wait for an ultrasound exam for around 12 weeks.

2) Does the pregnancy belly grow faster with twins?

In case you're expecting twins, you can expect to start showing even before the end of the first trimester (it's two babies!). Unlike when carrying a singleton that may not show until after 3 or 4 months, with twins you might show as early as 6 weeks!

3) Does one cramp more with twins?

In a twin pregnancy, the body produces high levels of pregnancy hormones. This means you can expect to feel earlier and more intense symptoms from pregnancy, such as heartburn, swelling, leg cramps, sleeping problems, and bladder discomfort.

On behalf of the editorial team at Parenthoodbliss, we follow strict reporting guidelines and only use credible sources, along with peer-reviewed studies, academic research institutions, and highly respected health organizations. To learn about how we maintain content accurate and up-to-date by reading our medical review and editorial policy.

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