First Week of Pregnancy – Your Body and Your Baby

First Week of Pregnancy - Your Body and Your Baby

In the first week of pregnancy, you’re actually not pregnant yet!

In fact, your period has just started.

This is because week 1 of pregnancy begins on the first day of your menstrual cycle.

Even though your baby has not yet been conceived, you’re in the time window which is classed as part of the nine months of pregnancy.

Why Is This The First Week Of Pregnancy?

Pregnancy is dated from the first day of your last menstrual period so doctors can work out an estimated due date.

Conception usually occurs about 14 days after the start of your period and pregnancy gestation is usually around 40 weeks.

We don’t know exactly how long it takes each woman to grow her baby, but the normal length is between 37 and 42 weeks, which means your due date is really a guess date!

So, this is why it’s called the first week of pregnancy – because it’s easier.

If you’d like to work out your baby’s approximate due date, try BellyBelly’s due date calculator.

Becoming pregnant is a life changing experience, planned or unplanned. It can be a rollercoaster of decisions and emotions. You might wonder if you’re ready to be a parent or worry about finances and your career.

People react to the idea of becoming parents very differently, and sometimes it can be a challenge to deal with all the different feelings. Talking to a trusted friend, family member or even journaling your thoughts can help you process your thoughts.

First Week of Pregnancy – Your Body

So let’s take a look at what’s happening to your body during the first week of pregnancy.

Once your period finishes, your endometrium (the inner lining of your uterus), begins thickening in preparation for implantation of a fertilised ovum.

This thickening is caused primarily by an increase in the hormone progesterone. If implantation does not take place, progesterone levels falls and your body gets rid of this thickened layer causing bleeding. You get your period.

1 Week Pregnant – Your Baby

In the first week of pregnancy, your baby is still a small, single celled egg, hiding in one of your ovaries. This egg is called an ovum and is only just visible to the naked eye. It’s completely unaware of what’s about to occur!

1 Week Pregnant – For The Men

Listen up men — there are a few things you can do to help increase your chances of conception in the next week or two.

Cutting back on caffeine, alcohol, smoking, and unhealthy processed foods (sugars and grain products) can have a positive impact on your health and fertility.

Here are some other things you may not know about that can give you a boost right now:

  • Stress can interfere with sperm production. Get plenty of sleep and try some relaxation techniques like massage or acupressure to help relieve stress.
  • Studies have shown that men who eat soy foods may have a lower sperm concentration than men who don’t eat soy foods. Avoid soy!
  • Another study published in Fertility and Sterility showed that your mobile phone may also affect your fertility. They found that men who used a hands-free device with a cell phone and kept their phone close to their testicles had impaired sperm quality.
  • Tight fitting underwear or environments where overheating can occur, for example, a hot spa, can also impact on sperm production.
  • While not necessary to guarantee conception, the female orgasm can certainly improve the chances of a fertilised ovum implanting successfully. This article talks you through the how and why. Maintaining intimacy and connection while planning to conceive and during pregnancy is very important.
You need the BellyBelly Birth & Early Parenting Immersion!
MAXIMISE your chances of getting the birth you want… MINIMISE your chances of a disappointing or traumatic birth experience. Feel MORE CONFIDENT heading into birth… GUARANTEED.
Last Updated: June 13, 2018


Kelly Winder is the creator of, a writer, doula (trained in 2005), and a mother of three awesome children. She's passionate about informing and educating fellow thinking parents and parents-to-be, especially about all the things she wishes she knew before she had her firstborn. Kelly is also passionate about travel, tea, travel, and animal rights and welfare. And travel.

loaded font roboto