Feeding

Breastfeeding Basics: Getting Started in the First Week

By Raised Editorial · Published 17 July 2026

The first week of breastfeeding is often the hardest. From colostrum to milk coming in, here is a biological breakdown of what to expect and how to establish a strong milk supply.

Breastfeeding is natural, but it is rarely easy in the beginning. It is a completely new biological skill that both you and your baby must learn simultaneously.

The first week is a whirlwind of hormones, physical recovery, and constant feeding. Understanding the biology of milk production can help alleviate the anxiety many new mothers feel when they wonder, "Is my baby getting enough?"

Here is a breakdown of what happens biologically during the first week of breastfeeding and how to set a strong foundation for your milk supply.

Days 1 to 3: The Colostrum Phase

For the first few days after birth, your breasts do not produce large volumes of white milk. Instead, they produce colostrum, often referred to as "liquid gold."

• What it is: Colostrum is thick, sticky, and often yellowish. It is highly concentrated with protein, fat-soluble vitamins, and vital antibodies (specifically Secretory IgA) that coat the baby's digestive tract to protect against infection.
• The Volume: You only produce tiny amounts of colostrum—roughly 1 to 4 teaspoons per day. This causes many mothers to panic, thinking they have "no milk."
• The Biology: Your baby's stomach on day one is only the size of a cherry or a marble. It can only hold about 5 to 7 milliliters per feed. Colostrum provides perfectly calibrated, dense nutrition without overwhelming their tiny stomach.

Your Goal in Days 1-3: Feed on demand. The baby will likely want to nurse constantly. This frequent stimulation sends signals to your brain (specifically the pituitary gland) to release prolactin, the hormone responsible for milk production.

Days 3 to 5: "Milk Coming In"

Between days 3 and 5, a massive hormonal shift occurs. The sudden drop in progesterone (which happens after the placenta is delivered) allows prolactin levels to surge.

Your breasts will transition from producing small amounts of colostrum to larger volumes of transitional milk.

• The Sensation: Your breasts may feel heavy, warm, full, and sometimes uncomfortably engorged.
• The Milk: The milk will become thinner, whiter, and far more voluminous.
• The Baby: Your baby's stomach has grown to the size of a walnut (Day 3) and then an apricot (Day 7), allowing them to take in about 1 to 2 ounces per feed.

Supply and Demand: The Golden Rule

Breast milk production operates on a strict principle of supply and demand.

Your breasts contain a protein called Feedback Inhibitor of Lactation (FIL). When your breasts are full of milk, FIL signals the brain to stop making more milk. When your breasts are empty, the lack of FIL signals the brain to make more milk rapidly.

Therefore, the most critical rule of the first week is: To make more milk, you must remove more milk.

• Nurse frequently (at least 8 to 12 times in a 24-hour period).
• Do not try to put a newborn on a strict feeding schedule. Follow their hunger cues (rooting, smacking lips, bringing hands to mouth).
• If the baby is not latching well or you are separated from your baby, you must express or pump milk every 2 to 3 hours to mimic a baby's feeding and tell your body to keep producing.

When to Seek Help

The American Academy of Pediatrics (AAP) and the World Health Organization (WHO) recommend exclusive breastfeeding for the first 6 months, but they also emphasize the importance of maternal support.

Breastfeeding may feel deeply uncomfortable as you learn the latch, but it should not cause agonizing pain, bleeding, or cracked nipples. If you are experiencing severe pain, or if your baby is not producing enough wet and dirty diapers (a key sign of milk intake), reach out to an International Board Certified Lactation Consultant (IBCLC) immediately. A small adjustment to positioning or latch can completely transform the experience.