To make it easier to transition a breastfed baby to a bottle, various types of bottles and nipples to mimic the feel of nursing. Again, you may have to try a few to find one that works for your baby.

What to look for when buying Bottles

Bottle material: Glass, silicone, plastic, and stainless steel are the most common materials.

●Plastic is light, ubiquitous, shatterproof and inexpensive, but parents worry about chemicals even in BPA-free plastic (read more about BPA in Important Safety Notes, below). Plastic bottles also deteriorate, so they need to be replaced regularly.

●Glass is heavy and can shatter (you can buy silicone sleeves that go over glass bottles to prevent this), but it’s BPA-free. Glass bottles are sold widely and last longer than plastic ones but are more expensive.

●Silicone bottles are light, unbreakable, BPA-free, and often soft but more expensive than plastic and glass. Often silicone bottles aren’t sold in drugstores or grocery stores, which can be inconvenient if a nipple cracks or breaks and you need a quick replacement.

●Stainless steel is light, unbreakable, BPA-free, and lasts for a long time, but like silicone, these bottles can be expensive and hard to find.

Bottle shape: Bottles come in a wide variety of shapes. Traditional ones are tall and slightly curved or angled. Many bottles on the market claim to be easier for babies to hold, have an ergonomic design, or angled necks to make them easier for you to hold. Wide-necked bottles may make measuring formula easier; they may also not fit into drink-holders on strollers or in cars.

Disposables: Bottles with drop-in plastic inserts filled with formula or breast milk can be handy while on the go and are easy to clean: just toss the liner and wash the nipple. Each insert can be used only once.

Venting systems: Many bottles are marketed as preventing colic; they may have straw-like components that fit into your bottle to prevent your baby from ingesting gas-causing air bubbles, or may have venting systems built into the nipple or bottom of the bottle. The jury’s still out on whether these systems work, but many parents firmly believe they do.

Size and number: The number of bottles you’ll need to own can range from about 4 to 12, depending on whether you’ll primarily be bottle-feeding or breastfeeding. Start with 4-ounce bottles. They’re perfect for the small amounts of breast milk or formula newborns eat in one sitting. Shift to 8- or 9-ounce bottles at about 4 months, or whenever your baby’s growing appetite makes bigger bottles more practical.