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What to expect in your first trimester

The Modern Midwife’s guide to the first stage of pregnancy

Author Marie Louise
Categories   First Trimester

The Edit

It may not seem real, those two pink lines or the word ‘pregnant’ sitting in front of you. Perhaps you are shocked, surprised or even terrified. Maybe it’s all the above. Whatever your circumstances, I’m here to help guide you through. In this article we will cover some of the ‘typical’ or likely signs of the beginning of your pregnancy. First, let’s take a look at how pregnancy is calculated.

A typical pregnancy lasts 40 weeks (280 days) although there is natural variation around this and 37–42 weeks is considered to be a healthy length of pregnancy too. Your due date is calculated from the first day of your last period, but conception is usually around two weeks after this day.

Pregnancy is divided into three trimesters:

  • The First Trimester covers week 1 to 13
  • The Second Trimester covers week 14 to 27
  • The Third Trimester covers week 28 to 40 (+)

Breaking your pregnancy down, there are a cascade of signs and changes, beginning with your First Trimester. It’s a time of tremendous change, growth and adaptation. Whether you are aware of it or not, your body will hastily begin preparations to provide the ideal environment for your new life.

It’s going to be an incredible journey which began with that all important fusion of an egg and a sperm. The meeting of these two Gametes or reproduction cells, sets into motion a whole sequence of genetically programmed events.

The first ‘micro’ action of the pregnancy is cell division of the fertilised egg. This egg ‘ball’ travels down the fallopian tube and to the uterus. It hangs out in the uterus for about two days and then implants into the lining of the uterus about four days after fertilisation. The hormones that normally trigger your periods now stand down and allow the new pregnancy hormones to hold onto the cells that are preparing to make an embryo, which develops around week five.

The first sign for a lot of women is (well used to be) that they have missed a period. These days, with the advances in healthcare, you can find out you’re pregnant before you are due to start your period. Some tests offer results five days prior to your due period.

Signs of early pregnancy include:

  • Missed period(s)
  • Nausea/vomiting
  • Sore boobs
  • Bloating
  • Feeling tired
  • Fluctuation of mood
  • Hypersensitive – particularly smell and taste

The effects above are down to the many hormonal changes which we will look at later. Initially, the main hormone that floods into your bloodstream in early pregnancy is the Human Chorionic Gonadotrophin (hCG) hormone. It’s the hormone that’s detected (in your urine) in all pregnancy tests, whether at home, or at your doctor’s.

It’s made by the embryo and later, by the placenta. They’re all in it together and even stimulate the thyroid gland. We can never underestimate the power of hormones as they are chemical messengers and carry information and instructions to precise destinations in the body. There’s a whole secret ‘micro underworld’ that’s set into motion - a hive of activity and growth.

These messengers ‘speak’ to the relevant tissues, instructing the organs to do their thing. Hormones are completely oblivious to the possible turmoil they can send a woman into. Nausea can range from mild to severe or be non-existent. Many women say they became sensitive to smells that spark the nausea or ‘go off’ of regular food and drinks, like coffee or veggies.

We know for sure that hunger (low blood sugar) is a trigger for nausea in pregnancy. Try to eat little and often - leave some biccies by your bedside to nibble on first thing. Try opening a window and doing some deep breathing in the morning too. This can help with the feel of nausea.

Rarely, the nausea and vomiting can be so excessive as to cause a condition known as Hyperemesis Gravidarum (HG). If you are vomiting several times a day and unable to keep food and drink down, let your GP know as you will need to be assessed and might need to go to hospital for some fluids.

Tiredness can kick in very early on and combined with nausea and/or vomiting, it can be crippling. Nap/rest/be horizontal whenever you can and never feel guilty about it. As early as three to four weeks, you could notice that you have sore or swollen boobs. It’s similar to the feeling some women get just before or during menstruation. You might recognise the feeling and it can be an exaggerated version.

You might notice that your nipples have darkened (or the area around the nipple looks darker). An increase in the production of oestrogen and progesterone in pregnancy will be responsible for changing your body in preparation for your baby.

Your breasts are already preparing for breast feeding and therefore get an extra supply of blood. Some women will begin to notice increase in breast size in the first few months. Others may have little or no difference, although later on there can be a significant increase in breast size.

If you feel the need to pee more often than usual, this is a common side effect of early pregnancy too. Again, not everyone notices or experiences many bladder changes early on; we are all different.

As well as the physical changes that come with the first trimester, it’s not uncommon for women to experience emotional fluctuations. Some describe the changes as an emotional rollercoaster which can take you from feeling ecstatically happy, to sad or outbursts of anger. If you have experienced Pre-Menstrual Syndrome or overt premenstrual changes, it can feel similar to that or an exaggerated version. If the pregnancy coincides with a time of stress or the thought of it is stressful/confusing, then it’s more likely you will feel emotional conflict.

During the first trimester you will also have your first midwife appointment and be offered several screening tests including your first scan at around 12 weeks. If you are experiencing a difficult start to your pregnancy, talk to your Midwife, your GP, a good friend or family member who will support you. There are countless women experiencing the changes in early pregnancy and rest assured, women have been experiencing the highs and lows of early pregnancy for millennia. You are not alone and it’s perfectly normal to question the whole idea of being pregnant.

Bringing a new life into the world is an amazing experience, but it’s not unusual to feel unsure or overwhelmed about some aspects or the idea of becoming a parent. This can be the case with a first pregnancy or subsequent pregnancies.

It also has to be said that some women don’t feel too many changes in the first trimester and there are cases of women who don’t even realise they are pregnant until later on. Whether you are aware of the effects of early pregnancy or not, one thing is for sure – your body knows what to do, is getting on with it and is preparing your baby for the best start that your body can offer them.

You've got this! 

Read what to expect in your second trimester here

Author Marie Louise

Marie Louise is an experienced Midwife, PTLLS adult educator and hypno-birthing teacher from the UK. She has travelled extensively to learn about midwifery in different cultures and has also practised in Australia. She runs ‘Modern Midwives Meetups’ which provide a safe space for midwives to share best practice and hear from experts in the maternity field. Marie Louise is a sought after expert and has most recently been invited to Parliament to discuss maternal mental health and maternity discrimination. She's also a communications partner for Child.Org, an equal opportunities charity for children and advises Cocoon Family Health, a perinatal mental health charity based in London.

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