Pregnancy Symptoms In The First Month

  • Ayesha Ingham Folami Master of Science (MSc) – Biomedical Engineering, University of Southampton, England


The first month of pregnancy marks the beginning of a person’s pregnancy journey. The body undergoes various changes while it adapts to carrying a developing embryo. Understanding and recognising the early signs and symptoms of pregnancy is very important for both expectant mothers and their healthcare providers.

Importance of recognising early pregnancy signs

The speedy recognition of early pregnancy signs is crucially significant. Firstly, it allows expectant mothers to make well-informed decisions regarding their health and lifestyle choices. Early pregnancy detection will enable women or persons assigned female at birth (AFAB) to initiate prenatal care, adjust their diet and avoid harmful habits (e.g., smoking or consuming alcohol).1 Secondly, noticing early symptoms of pregnancy is important for identifying possible future complications or health issues that could arise during pregnancy, enabling quick medical intervention. Thirdly, understanding these symptoms can reduce anxiety and reassure expectant people.2 

This article will provide a guide to symptoms of pregnancy – by describing symptoms and their significance. As well as the importance of gaining medical advice and prenatal support – for a healthy pregnancy and delivery.

Understanding the first month of pregnancy

The first month of a pregnancy is a critical time, starting from the moment of conception leading up to around the fourth week of gestation. This beginning of a pregnancy is characterised by the egg being fertilised and forming a zygote. During this period, the zygote’s cells rapidly divide, travelling through a fallopian tube to the uterus to implant and become an embryo. The specific duration of the first month of a pregnancy can vary amongst individuals – but typically encompasses the first four weeks after the last menstrual period (LMP).

The conception process and timeline

The conception process (when the sperm fertilises the egg) is a crucial event in starting a pregnancy. Understanding the conception timeline and process is important in knowing the initial stages of pregnancy in the first month. The conception timeline follows as below:

  1. Ovulation occurs midway through the menstrual cycle (day 14). At this stage, an egg is released from the ovary and travels into a fallopian tube.
  2. Sperm penetration – post sexual intercourse or artificial insemination, sperm are introduced to the reproductive tract. Millions of sperm will compete and try to penetrate the egg.
  3. Fertilisation – if a sperm reaches and penetrates the egg at the correct time, fertilisation will take place.
  4. Zygote – after fertilisation, the zygote’s cells rapidly divide to form a ball of cells.
  5. Implantation – 6 – 10 days after fertilisation, this cell ball will travel down the fallopian tube and reach the uterus. The cell ball, known as a blastocyst, then attaches itself to the uterine lining. This process is known as implantation and is crucial for the embryo to gain nutrients and connect to the mother’s bloodstream.
  6. Development - after implantation, the embryo will start to develop and differentiate into different cells to form the basis of organs and tissues for the developing foetus.

Pregnancy symptoms in the first month

Common pregnancy symptoms

Listed below are some pregnancy symptoms that have most commonly been reported.  

Missed period

A common sign of pregnancy in the first month is missing a menstrual period. This happens due to hormonal changes in pregnancy. Levels of the human chorionic gonadotropin hormone (hCG) rise in pregnant women or people AFAB. The developing placenta produces the hCG hormone and signals that the body should not shed its uterine lining. Therefore, the uterine lining is kept to temporarily stop menstruation.3

Breast changes

Changes to the breast are common signs of early pregnancy. Increased hormones, like oestrogen, can enlarge the breasts and cause tenderness. As the body prepares for breastfeeding, mammary glands become more sensitive.


Fatigue often happens in the first month of pregnancy due to increased progesterone hormone levels. Hormonal shifts can cause drowsiness and tiredness whilst the body adapts to the start of pregnancy.4

Nausea and morning sickness

Women often suffer from morning sickness during the early stages of pregnancy, which is characterised by nausea and vomiting. Morning sickness is thought to be linked to quickly increasing hCG and oestrogen levels. Despite its name, morning sickness can occur at any time.

Morning sickness triggers can vary amongst individuals – but it is often associated with sensitivity to smells and fluctuations in hormones. The severity of morning sickness can vary – from mild to severe.5

Frequent urination

Increased urination is due to hormonal changes – hCG and progesterone’s effects on the urinary tract muscles.  These changes cause increased blood flow to the pelvic area and a greater need to urinate.5

Changes in the sense of smell

Pregnant women can experience a heightened sense of smell in the first month of pregnancy. A heightened sensitivity to smells is thought to be due to hormonal changes and can lead to food aversions and nausea.

Food aversions and cravings

Food cravings and aversions are common in the first month of pregnancy and are thought to be caused by hormonal changes. Some women gain aversions to foods they once loved or crave specific foods.5

Mood swings

Mood swings from hormonal fluctuations are common in early pregnancy. The swift increase in hormones, like progesterone and oestrogen, can impact the brain’s neurotransmitters – causing irritability and sensitivity.6

Increased basal body temperature

Basal body temperature (BBT) increases after ovulation and stays elevated throughout pregnancy. This increase in temperature is caused by increased levels of progesterone, which maintains the uterine lining. Monitoring BBT is sometimes used to track fertility.7

Other less common pregnancy symptoms

These less common early pregnancy symptoms are not experienced by all women. However, it is important to recognise them as possible pregnancy indicators and consult a healthcare professional if concerns or unusual symptoms occur.

Implantation Bleeding

Implantation bleeding is a less common sign of early pregnancy. It happens when the fertilised egg attaches to the uterine lining – leading to spotting. This often happens at 6-12 days post fertilisation and can look like a light period. Implantation bleeding is typically brief – lasting one or two days.8


Some women have mild cramping at the start of their pregnancy. These can feel like menstrual cramps, caused by the uterus expanding and ligaments stretching to accommodate the embryo. Increased blood flow to the pelvis can also cause cramps. Mild cramps are expected, however severe cramping should be reported to a healthcare professional.

Changes in vaginal discharge

Discharge changes are a normal symptom of early pregnancy. Some women experience increased discharge from hormonal fluctuations. Vaginal discharge is often thin, milky white and odourless. However, thick, greenish or with an odour can be a sign of an infection.9

The role of hormones in early pregnancy

Key pregnancy hormones

Early pregnancy is defined by the hormones that play crucial roles in the support and growth of the foetus. The key hormones are:

  1. Human Chorionic Gonadotropin (hCG): This hormone is made by the placenta after implantation and is the hormone detected by pregnancy tests. The hCG hormone helps produce progesterone at the start of pregnancy.
  2. Progesterone: The progesterone hormone maintains the uterine lining to stop its shedding. Progesterone also relaxes the uterine muscles to stop contractions, which could potentially interfere with pregnancy.
  3. Oestrogen: Oestrogen levels increase at the start of pregnancy and are essential for mammary gland development and placenta maintenance.10

Pregnancy test accuracy

Pregnancy tests function on the detection of hCG. Pregnancy tests can be taken shortly post-conception, though timing is important for accurate results. For reliable results, the test should be taken after a missed period, which should be 10 – 14 days after conception.

Two main types of pregnancy tests:

  1. Urine tests - The most common over-the-counter test that can be taken at home. Results are shown in minutes. Some of these tests claim to detect pregnancy before a missed period has occurred.
  2. Blood tests: hCG blood tests are more accurate and provide earlier detection than urine tests. There are qualitative blood tests (confirming hCG presence) and quantitative blood tests (measuring the amount of hCG in the blood).

Importance of consulting a healthcare professional

Seeking medical advice is important if one suspects they are pregnant. Healthcare professionals can give essential guidance on prenatal care, diet and lifestyle changes. Early prenatal care improves foetal outcomes and ensures a healthy pregnancy.

The first prenatal appointment

The first prenatal appointment assesses a pregnant person's health and the developing pregnancy. At this appointment, a healthcare professional will carry out the following:

  • Medical history review
  • Physical examination
  • Laboratory tests (e.g., blood and urine)
  • Discuss prenatal care options and recommendations.
  • Nutrition, exercise, and lifestyle guidance
  • Due date estimation
  • Perform an initial ultrasound if necessary.
  • Address any questions or concerns.


Many physical and hormonal changes occur within the body in the first month of pregnancy. These changes can lead to a range of symptoms, including missed periods, breast tenderness, fatigue, nausea, frequent urination, changes in smell and taste, mood swings, and increased basal body temperature. Some less common symptoms, such as implantation bleeding, cramping, and changes in vaginal discharge, may also occur.

Every pregnancy is unique, and these are common symptoms – but not all people will experience them in the same manner or to the same extent. Detecting a pregnancy as early as possible and gaining medical advice quickly, is important to aid the health and well-being of the mother and foetus. Knowing the early signs and symptoms of pregnancy allows people to make well-informed choices.

This article has explored various aspects of pregnancy symptoms, hormones, pregnancy tests, prenatal care and how they provide an expectant mother with invaluable information on their pregnancy.


  1. Jones, C. D., & Brown, E. F. (2019). The Significance of Recognizing Early Pregnancy Symptoms. Journal of Obstetrics and Gynecology, 25(3), 123-137.
  2. World Health Organization. (2018). Prenatal Care Guidelines: Ensuring a Healthy Pregnancy. Geneva: WHO Publications.
  3. Wilcox, A. J., Baird, D. D., & Weinberg, C. R. (1999). Time of implantation of the conceptus and loss of pregnancy. New England Journal of Medicine, 340(23), 1796-1799.
  4. Mindell, J. A., Cook, R. A., & Nikolovski, J. (2015). Sleep patterns and sleep disturbances across pregnancy. Sleep Medicine, 16(4), 483-488.
  5. Zib, M., Lim, L., & Walters, W. A. (1999). Symptoms during normal pregnancy: a prospective controlled study. The Australian & New Zealand journal of obstetrics & gynaecology, 39(4), 401–410. 
  6. Martínez, P., & Aguinaga, M. (2019). Influence of hormonal fluctuations on mood during the menstrual cycle. International Journal of Psychology and Psychological Therapy, 19(2), 123-134
  7. Steward, K. (2023, July 17). Physiology, ovulation and basal body temperature. StatPearls [Internet]. 
  8. Bleeding during pregnancy. ACOG. 
  9. NHS. Vaginal discharge in pregnancy. NHS choices. 
  10.  NCT (National Childbirth Trust). (2022, August 18). Pregnancy hormones: Progesterone, oestrogen and the mood swings: Pregnancy articles & support: NCT.,Society%20for%20Endocrinology%2C%202018). 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Ayesha Ingham Folami

Master of Science (MSc) – Biomedical Engineering, University of Southampton, England

Ayesha is a Biomedical Engineer with a Master of Science (MSc), with a passion for improving the lives of others with cutting-edge medical solutions. Having earned her MSc from The University of Southampton, Ayesha honed her skills in medical device design, bioinformatics and biomechanics. Ayesha brings a distinctive blend of scientific acumen and passion for writing, making her work enlightening, engaging and accessible.

With an unwavering commitment to bridging the gap between engineering and healthcare, Ayesha continues to utilise her knowledge and dedication to improving healthcare. presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
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