When choosing pajamas for babies, parents often struggle with priorities like "softness," "breathability," and "non-restrictiveness" — and knitted fabric, with its naturally body-hugging properties, has long been a popular choice for baby pajamas. However, not all knitted pajamas are the same: some feel as light as a cloud, while others offer warmth like a small blanket. The key difference lies in the weave. Among them, Single Jersey and Interlock are the two most comfortable weaves for baby pajamas, each with unique advantages suited to different seasons and needs. Today, we’ll break down the characteristics of these two weaves to help you pick the perfect knitted pajamas that let your baby sleep soundly all night.
Many parents find terms like "Jersey" and "Interlock" confusing, but they’re both basic knitted weaves, differing mainly in structure:
Jersey (Single-sided Knit): A "single-sided weave" where only one side of the fabric has clear stitch patterns, while the other side is relatively smooth. It resembles a lightweight knitted mesh, with tiny gaps between fibers, resulting in a thin, lightweight fabric that feels soft and smooth without noticeable bulk.
Interlock (Double-sided Knit): Also known as "rib knit," it’s a "double-sided weave" with symmetrical rib patterns on both sides of the fabric, creating a denser structure. It’s like two layers of thin knitted fabric woven together, forming tiny air pockets in between. The fabric feels thick and elastic, with quick rebound after stretching and minimal deformation.
In simple terms, Jersey is "lightweight and streamlined," while Interlock is "double-layered for protection." The differences between the two weaves directly determine the comfort and suitable scenarios of the pajamas.
If your baby is particularly sensitive to heat, or if you’re choosing pajamas for summer, Jersey-knit pajamas are a must-have. Their advantages perfectly match babies’ summer needs:
The single-sided Jersey weave creates tiny air vents across the fabric, like "small windows" in the pajamas — even if your baby sweats while sleeping, heat can quickly escape through these vents, rather than being trapped between the skin and fabric. For example, when your baby rolls over or kicks off the blanket at night, Jersey pajamas release body heat promptly, preventing colds caused by sweat sticking to the skin. They’re especially ideal for active, "little firecracker" babies who sweat a lot while sleeping.
High-quality Jersey pajamas (such as combed cotton Jersey) are extremely light, with almost no "存在感" (sense of weight) when worn. They won’t pull on your baby’s small arms and legs like thicker fabrics. When your baby rolls over or kicks their legs in sleep, the pajamas stretch freely with their movements. Even young babies who have just learned to roll over can move easily without hindering the stretching of their limbs during sleep.
Jersey’s loose fiber structure absorbs moisture much faster than ordinary woven fabrics — when your baby sweats a little at night, Jersey quickly wicks the sweat to the fabric surface, then evaporates it through the air vents, so your baby won’t feel "sticky." For instance, if your baby has mild night sweats in the early morning, Jersey pajamas dry quickly, preventing them from waking up due to dampness.
That said, Jersey pajamas have limitations: their thin texture means poor warmth retention, so they’re only suitable for warm environments above 20°C (68°F). Wearing them in winter can easily make babies cold, so they’re better used as summer pajamas or "inner layers" for spring and autumn.
As temperatures drop in autumn and winter, baby pajamas need to balance "warmth" and "non-bulkiness" — this is where Interlock weave shines. It’s like wrapping your baby in a "lightweight warm blanket" without feeling restrictive:
The double-sided Interlock weave creates an invisible "air layer" in the fabric, which acts like a "thermal film" to trap your baby’s body heat and reduce heat loss. For example, when the room temperature is 15–20°C (59–68°F) in late autumn, a single layer of Interlock pajamas keeps your baby warm without making them sweat like fleece pajamas. They’re perfect for air-conditioned or heated rooms, avoiding colds caused by temperature fluctuations.
Interlock fabric has stronger stretchability than Jersey, with fast rebound — when worn, it fits closely to your baby’s body curves without leaving red marks. Even if your baby curls up like a "little shrimp" while sleeping, the pajamas contract with their body and won’t feel tight or uncomfortable. For babies in the crawling stage who roll over and crawl frequently at night, Interlock’s elasticity allows for more free movement.
Interlock’s dense structure means stronger fiber connections, making it more durable than Jersey. Baby pajamas need frequent washing, but Interlock fabric resists pilling and deformation even after multiple washes. Even after a dozen washes, it remains smooth in shape and soft to the touch, unlike ordinary Jersey which may become loose and saggy — offering better value for money.
The minor downside of Interlock? Its dense structure makes it slightly less breathable than Jersey, so it can feel stuffy in summer. It’s more suitable for cool environments between 10–20°C (50–68°F), making it a "mainstay" for autumn and winter baby pajamas.
Now that you know the differences between the two weaves, keep these 3 tips in mind to avoid mistakes when shopping:
Whether choosing Jersey or Interlock, opt for 100% cotton or cotton blends (e.g., 95% cotton + 5% spandex) — pure cotton is skin-friendly and non-irritating, while a small amount of spandex enhances elasticity to prevent tightness during movement. At the same time, always check safety standards: the pajamas must meet GB 31701-2015 Category A (China’s dedicated standard for infant textiles) to avoid harmful substances like formaldehyde and fluorescent brighteners. For imported products, look for OEKO-TEX® Standard 100 certification for extra peace of mind.
Summer/Room temperature ≥25°C (77°F): Choose Jersey pajamas, preferably thin styles (weight: 120–160g/m²) such as combed cotton Jersey, for cool comfort without stuffiness.
Spring/Antumn/Room temperature 18–25°C (64–77°F): Pair Jersey pajamas with a thin sleep sack, or choose lightweight Interlock pajamas (weight: 180–220g/m²).
Autumn/Winter/Room temperature 10–18°C (50–64°F): Choose thickened Interlock pajamas (weight: 220–260g/m²), or pair Interlock pajamas with a medium-thickness sleep sack for warmth without bulk.
Details matter more for baby pajamas than adult ones:
Choose "seamless stitching" for seams: Both Jersey and Interlock pajamas may have seams, but seamless stitching ensures flat seams that won’t rub your baby’s delicate skin (especially around the neck, armpits, and ankles).
Opt for "wide elastic necklines": Wide necklines won’t pinch your baby’s chin or neck when putting on/taking off the pajamas. Interlock pajamas with elastic necklines stretch repeatedly, making them suitable for babies with larger head circumferences.
Avoid complex decorations: Steer clear of styles with sequins, small buttons, or long drawstrings. Jersey fabric is thin, so decorations may fall off and be a choking hazard; Interlock fabric is thick, so complex decorations add unnecessary bulk and disrupt sleep.
Neither Jersey nor Interlock knitted pajamas are inherently "better" — the right choice depends on "whether they fit your baby’s needs." For heat-sensitive babies or summer use, choose Jersey; for cold-sensitive babies or autumn/winter use, choose Interlock. The key is to consider the season, room temperature, and your baby’s physical condition (e.g., prone to sweating vs. cold hands/feet) — this way, you’ll find pajamas your baby will "refuse to take off" because they’re so comfortable.
After all, for babies, a breathable, non-stuffy, snug-but-not-tight pair of pajamas is the secret to sound sleep all night. And for parents, watching their baby sleep soundly with a rosy cheeks in soft knitted pajamas is probably the most reassuring moment of all.
