Dr. Barra OBriain, MD,Local Family Physician Vancouver

discusses bleeding in early pregnancy.

Common Maternal Symptoms

Surging hormones (especially hCG and progesterone) cause significant physical and emotional changes:

  • Nausea and vomiting (“morning sickness”)

  • Fatigue and extreme tiredness

  • Tender, swollen breasts

  • Frequent urination

  • Mood swings, bloating, and food cravings or aversions

The first trimester is the initial stage of pregnancy, spanning from week 1 through week 12 or 13 (roughly the first three months). It begins on the first day of your last menstrual period—before conception even occurs—and covers the rapid transformation of a single cell into a fully formed fetus.

Fetal Development Highlights

  • Weeks 1–4: Conception occurs, and the fertilized egg implants into the uterine lining.

  • Weeks 5–8: The neural tube (which becomes the brain and spinal cord), heart, main organs, and tiny arm/leg buds begin forming. The heart starts beating around week 5 to 6.

  • Weeks 9–12: The embryo officially becomes a fetus. Facial features, fingers, toes, and fingernails form. All major organs and body systems are in place by the end of week 12.

Dr. Nardia Strydom, MD, Local Family Physician

discusses Body Mass Index (BMI) and Pregnancy

Care & Milestones Most people schedule their first prenatal appointment during this trimester to confirm the pregnancy, estimate a due date via ultrasound, perform routine blood tests, and begin taking prenatal vitamins (like folic acid) to support early development.

How food allergies can affect mental health
  1. Stress and anxiety
    • People with serious food allergies may experience ongoing worry about accidental exposure, especially if reactions can be life-threatening.
    • This can lead to increased anxiety, hypervigilance, and fear around eating, traveling, social events, or dining out.
  2. Social isolation
    • Food allergies can make school, work, parties, restaurants, and family gatherings more challenging.
    • Feeling different or excluded may contribute to loneliness, low mood, or reduced quality of life.

Dr. Heather Jenkins, MD, CCFP, Local Family Physician

discusses nausea in pregnancy

Dr. Karen Nordahl, MD, Family Physican, Vancouver

discusses testing after you become pregnant.

Dr. Elise Balaisis, MD, Local Family Physician

discusses first trimester prenatal visits.

RD Andy Desantis, Toronto, Ontario

Educational video describing Soy Food Allergies

True Allergy vs. Pregnancy Aversion/Intolerance

  • IgE Food Allergy: Involves the immune system. Symptoms include hives, swelling of the lips/tongue, nasal congestion, tingling in the mouth, or wheezing.

  • Food Intolerance or Aversion: Driven by hormones and an enhanced sense of smell. Symptoms are purely digestive (nausea, vomiting, aversion to certain textures or odors) without skin or respiratory involvement.

Why Allergies Shift in Early Pregnancy

  • Immune Reprogramming: The body transitions to a Th2-dominant immune state to prevent rejecting the embryo, which can make you more prone to histamine release and antibody (IgE) responses.

  • Hormonal Spikes: Surging levels of estrogen and progesterone affect mast cells and gut permeability, heightening sensitivities.

  • Overlap with Morning Sickness: Digestive symptoms like nausea, cramping, and bloating can make it hard to tell the difference between typical first-trimester morning sickness and a mild food reaction.

Dr. Karen Nordahl, MD, Family Physican, Vancouver

discusses Can Exercise Cause Miscarriage?

Why Mental Health Shifts in Early Pregnancy

  • Hormonal Surges: Rapid spikes in estrogen and progesterone directly alter neurotransmitters like serotonin and dopamine, triggering mood swings, irritability, or sudden sadness.

  • Physical Exhaustion: Constant nausea, fatigue, and poor sleep severely diminish your emotional coping reserves.

  • Miscarriage Anxiety: Fear of loss before the 12-week mark makes early pregnancy a high-stress waiting game for many.

  • Identity & Life Transitions: Worrying about finances, career adjustments, relationship dynamics, or ambivalence about becoming a parent is completely normal.